The molality of an aqueous NaBr solution is 2.50 m. What is the mass percent of NaBr?
(NaBr molar mass = 102.9 g/mol)
Answer is  20.5% - just need the steps - thanks!

Answers

Answer 1

To find the mass percent of NaBr in the solution, we first need to calculate the mass of NaBr present in 1 kg of the solution.



Molality (m) = moles of solute / mass of solvent in kg  Here, the molality is given as 2.50 m, which means that there are 2.50 moles of NaBr present in 1 kg of the aqueous solution. Mass of NaBr = molar mass x moles, Mass of NaBr = 102.9 g/mol x 2.50 mol = 257.25 g. Now, we can calculate the mass percent of NaBr in the solution: Mass percent = (mass of NaBr / total mass of solution) x 100% .



Total mass of solution = mass of NaBr + mass of water Since we know that the molality is 2.50 m, we can assume that 1 kg of the solution contains 1 kg - (257.25 g / 1000 g) = 0.74275 kg of water. Total mass of solution = 1 kg = 1000 g
Mass percent = (257.25 g / 1000 g) x 100% = 25.725%, Therefore, the mass percent of NaBr in the solution is 20.5% (rounded to one decimal place).

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Related Questions

δ s is positive for the reaction ________. 2 kclo3 (s) → 2kcl (s) 3 o2 (g) pb2 (aq) 2cl- (aq) → pbcl2 (s) co2 (g) → co2 (s) hcl (g) nh3 (g) → nh4cl (s) 2 ca (s) o2 (g) → 2 cao (s)]

Answers

Hi, I'd be happy to help with your question. In order to determine if δS (change in entropy) is positive for the given reaction, we need to consider the states of the reactants and products. A positive δS indicates an increase in randomness or disorder in the system.

The given reaction is:
2 KClO3 (s) → 2 KCl (s) + 3 O2 (g)

Here, two moles of solid potassium chlorate (KClO3) decompose to produce two moles of solid potassium chloride (KCl) and three moles of gaseous oxygen (O2).

To determine if δS is positive for this reaction, we compare the initial and final states:

Initial state: 2 moles of solid KClO3
Final state: 2 moles of solid KCl + 3 moles of gaseous O2

Since the reaction produces more gaseous molecules (3 moles of O2) than there were initially (0 moles of gas), there is an increase in randomness or disorder in the system. Therefore, δS is positive for the reaction.

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what is the volume of a gas that exerts a pressure of 457 mm hg if it exerted a pressure of 2.50 atm when its volume was 25.0 ml? group of answer choices a.9.62 ml b.6.01 ml c.25.0 l d.1.80 l e.0.104 l

Answers

Rounding off to two significant figures, the answer is 104 mL, which is approximately equal to 0.104 L..

We can use Boyle's Law to solve this problem:

P1V1 = P2V2

where P1 and V1 are the initial pressure and volume, respectively, and P2 and V2 are the final pressure and volume, respectively.

Converting the initial pressure of 2.50 atm to units of mmHg:

2.50 atm x 760 mmHg/atm = 1900 mmHg

Substituting the given values into the equation and solving for V2, we get:

V2 = (P1V1)/P2 = (1900 mmHg x 25.0 mL) / 457 mmHg

V2 = 103.95 mL

Therefore, the volume of the gas that exerts a pressure of 457 mmHg is 103.95 mL.

Rounding off to two significant figures, the answer is 104 mL, which is approximately equal to 0.104 L.

Hence, the correct option is (e) 0.104 L.

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As with most typical calorimetry experiments, this lab will measure the change in temperature of a substance in this case water) as a chemical reaction takes place. Using this temperature data, the enthalpy of reaction and/or enthalpy of combustion can be determined. To prepare you for these calculations, sample data gathered from the combustion of kerosene are provided below. By answering the questions that follow and performing these calculations, you will have a better understanding of this part of the data analysis you will complete for this lab. 1. In a hypothetical experiment, you and your lab partner run a soda-can calorimeter experiment to determine the enthalpy of combustion for kerosene. Using the terms qcomb, qrxn, and qwater, what is the mathematical expression that relates the flow of heat in this experiment?

Answers

This expression states that the heat of the reaction is equal to the negative sum of the heat of combustion and the heat absorbed by water. This relationship is based on the principle of conservation of energy, where the total energy in the system remains constant.

The mathematical expression that relates the flow of heat in this experiment is qcomb = -qrxn = -qwater, where qcomb is the heat released by the combustion of kerosene, qrxn is the heat absorbed by the reaction, and qwater is the heat absorbed by the water in the calorimeter.
In a calorimetry experiment measuring the enthalpy of combustion for kerosene, the heat flow can be described using the terms qcomb (heat of combustion), qrxn (heat of reaction), and qwater (heat absorbed by water). The mathematical expression that relates the flow of heat in this experiment is:

qrxn = - (qcomb + qwater)
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what is the lowest resonant frequency (in hz) of a tube made by joining the open-ended tube of part (a) to the open end of the closed tube of part (b)?

Answers

In general, the resonant frequency of an open-ended tube is given by the formula f = (n/2L)*v, where n is an integer, L is the length of the tube, and v is the speed of sound. The resonant frequency of a closed tube is given by f = (n/4L)*v, where n is an odd integer.

To find the lowest resonant frequency of the combined tube, we first need to understand the properties of open-ended and closed tubes.
An open-ended tube has both ends open and supports all harmonic frequencies. Its fundamental frequency (the lowest frequency) is given by the formula: f = v / (2 * L_open)
where f is the fundamental frequency, v is the speed of sound, and L_open is the length of the open-ended tube.
A closed tube has one end closed and supports only odd harmonic frequencies. Its fundamental frequency is given by the formula: f = v / (4 * L_closed)
where L_closed is the length of the closed tube.
When you join the open end of the closed tube to the open-ended tube, you create a new tube with a total length of L_total = L_open + L_closed. This new tube is an open-ended tube, as both ends are now open. To find the lowest resonant frequency (in Hz) of the combined tube, use the open-ended tube formula: f = v / (2 * L_total)
Substitute L_total with the sum of the lengths of the individual tubes (L_open + L_closed), and use the speed of sound (v = 343 m/s for air at room temperature) to calculate the lowest resonant frequency.

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calculate the ph of 50.0ml of h20 following the addition of 1.00 ml of 0.60 m naoh

Answers

For calculating the pH of the solution after adding 1.00 mL of 0.60 M NaOH to 50.0 mL of H2O, the following steps are followed:

Firstly, the moles of NaOH added are calculated:

moles = volume × concentration

moles = 0.001 L (1.00 mL converted to liters) × 0.60 mol/L

          = 0.0006 mol

Later, the moles of OH⁻ ions are determined:
Since NaOH is a strong base and dissociates completely in water, the moles of OH⁻ ions will be equal to the moles of NaOH.
Therefore, the moles of OH⁻ = 0.0006 mol

Now, the concentration of OH⁻ ions when total volume = 50.0 mL H2O + 1.00 mL NaOH = 51.0 mL = 0.051 L:

Concentration = moles / total volume

Concentration = 0.0006 mol / 0.051 L

                        = 0.01176 mol/L

The pOH is:
pOH = -log10[OH⁻]
pOH = -log10(0.01176) ≈ 1.93

And, finally the pH:
pH + pOH = 14 (for aqueous solutions at 25°C)
pH = 14 - pOH
pH = 14 - 1.93 ≈ 12.07

Hence, the pH of the solution after adding 1.00 mL of 0.60 M NaOH to 50.0 mL of H2O is approximately 12.07.

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A reagent bottle is labeled 0.255 M K2SO4.
(a) How many moles of K2SO4 are present in 25.0 mL of this solution?
(b) How many mL of this solution are required to supply 0.0600 mol of K2SO4?
(c) Assuming no volume change, how many grams of K2SO4 do you need to add to 1.50 L of this solution to obtain a 0.800 M solution of K2SO4?
(d) If 40.0 mL of the original solution are added to enough water to make 135 mL of solution, what is the molarity of the diluted solution?

Answers

First we need to calculate the number of moles of K₂SO₄ (potassium sulfate) in 25.0 mL of 0.255 M solution.

How many moles of potassium sulfate are present? What is the volume and grams of potassium sulfate required according to the question?

a) 0.255 moles K₂SO₄ / 1 L solution * 0.0250 L solution = 0.006375 moles K₂SO₄

Therefore, there are 0.006375 moles of K₂SO₄ present in 25.0 mL of this solution.

b) To calculate the volume of 0.255 M K₂SO₄ required to supply 0.0600 mol of K₂SO₄:

0.0600 moles K₂SO₄ / 0.255 moles per L = 0.235 L

0.235 L * 1000 mL/L = 235 mL

Therefore, 235 mL of this solution are required to supply 0.0600 mol of K₂SO₄.

(c) To prepare a 0.800 M K₂SO₄ solution from 1.50 L of 0.255 M K₂SO₄ solution:

Let x be the mass of K₂SO₄ required in grams. We can use the formula:

M₁V₁ = M₂V₂

where M₁ will represent initial concentration, V₁ will represent  the initial volume, M₂ will represent  the final concentration, and V₂ will represent the final volume.

0.255 M * 1.50 L = 0.800 M * 1.50 L + x grams / (174.26 g/mol)

x = (0.255 M * 1.50 L - 0.800 M * 1.50 L) * 174.26 g/mol = 34.90 g

Therefore, 34.90 grams of K₂SO₄ are needed to prepare 1.50 L of a 0.800 M K₂SO₄ solution.

(d) To calculate the molarity of the diluted solution:

M₁V₁ = M₂V₂

The initial volume is 40.0 mL, and the final volume is 135 mL, which means that the dilution factor is:

V₂/V₁ = 135 mL / 40.0 mL = 3.375

The final concentration can be calculated as:

M₂ = M₁ / (V1/V2) = 0.255 M / 3.375 = 0.0754 M

Therefore, the molarity of the diluted solution is 0.0754 M.

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if you want a solution that is 0.100m in ions, how many grams of na2so4 must you dissolve in 125g of water? (assume total dissociation of the ionic solid)

Answers

The first step in solving this problem is to calculate the number of moles of ions required to make a 0.100 M solution. Since [tex]Na_{2} SO_{4}[/tex] dissociates completely in water to form three ions (2 [tex]Na^{+}[/tex] ions and 1 [tex]SO_{4} ^{2-}[/tex] ion), the total number of moles of ions required is:

0.100 M × 3 moles = 0.300 moles

Next, we can use the formula:

moles = mass / molar mass

to calculate the mass of [tex]Na_{2} SO_{4}[/tex] required. The molar mass of [tex]Na_{2} SO_{4}[/tex] is:

2(22.99 g/mol) + 1(32.06 g/mol) + 4(16.00 g/mol) = 142.04 g/mol

So, we have:

0.300 moles = mass / 142.04 g/mol

mass = 0.300 moles × 142.04 g/mol = 42.61 g

Therefore, we need to dissolve 42.61 g of [tex]Na_{2} SO_{4}[/tex] in 125 g of water to make a 0.100 M solution of ions.

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which element has a ground-state electron configuration of kr 5s24d3 a. Nb b. Mn c. Tc d. Ru

Answers

The correct answer is d. Ru (Ruthenium). The electron configuration of Ru is [tex][Kr] 5s^2 4d^6[/tex], but when it is in its ground state, one of the 4d electrons is promoted to the 5s orbital.

Ruthenium is a rare transition metal element that has the atomic number 44 and the symbol Ru. It is part of the platinum group of metals, which also includes elements like platinum, palladium, and rhodium. It has a silvery-white metallic appearance and is one of the densest elements, with a density of 12.4 g/cm³. It has a high melting point of 2,334°C and a boiling point of 4,696°C. It is a hard, brittle metal that is resistant to corrosion and oxidation. It is used in various industrial and technological applications, such as in the production of hard disk drives, electrical contacts, and jewelry.

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select the single best answer. assuming it is planar, is the following ion aromatic, antiaromatic, or not aromatic?aromatic antiaromatic not aromatic

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Assuming it is planar, the answer depends on the number of pi electrons in the ion. If the ion has 4n+2 pi electrons, it is aromatic. If it has 4n pi electrons, it is antiaromatic. If it has any other number of pi electrons, it is not aromatic.

Aromaticity is a property that arises from the cyclic delocalization of pi electrons in a molecule. If a molecule is planar and has 4n+2 pi electrons, where n is an integer, it is considered to be aromatic. The term "aromatic" originally referred to the pleasant smell of certain compounds, but it now refers to a specific type of electronic structure. Aromatic compounds are known for their stability, reactivity, and unique physical and chemical properties. On the other hand, if a molecule has 4n pi electrons, where n is an integer, it is considered to be antiaromatic. Antiaromatic compounds are generally less stable and less reactive than aromatic compounds. If a molecule has any other number of pi electrons, it is not aromatic.

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Data And Report Submission - Recrystallization Of Acetanilide Yes Recrystallization Are you completing this experiment online?. Why is activated charcoal added to the solution in this experiment?

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In the recrystallization of acetanilide experiment, activated charcoal is added to the solution to remove impurities and improve product purity.

Activated charcoal is a highly porous material that can adsorb impurities, resulting in a cleaner and more pure acetanilide product after recrystallization.

During the experiment, the acetanilide is first dissolved in a hot solvent to form a saturated solution. Activated charcoal is then added to this hot solution, where it adsorbs any colored or unwanted impurities present in the mixture.

After adding the activated charcoal, the solution is usually filtered to remove both the charcoal and the impurities bound to it. This leaves behind a clearer solution containing dissolved acetanilide.

As the solution cools, the acetanilide recrystallizes, and the purified crystals can be collected by filtration. The use of activated charcoal in this step is crucial for obtaining a high-purity final product, as it effectively removes contaminants from the solution.

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equal volumes of 0.2 sodium carbonate and 0.4 hydrochloric acid are combined. write the net ionic equation of the reaction

Answers

The reaction's net ionic equation will only include the species that change chemically. The net ionic equation is:

[tex]CO_3^{2-} (aq) + 2H^{+} (aq) = > H_2O (l) + CO_2 (g)[/tex]

What exactly is an ionic equation?

Ionic equations are chemical equations that express the formulas of dissolved aqueous solutions as individual ions.

Why is the ionic equation significant?

A chemical equation is used to express what we believe is happening in a chemical reaction. Writing net ionic equations is one of the most useful applications of the concept of principal species.

For the reaction of sodium carbonate ([tex]Na_2CO_3[/tex]) and hydrochloric acid (HCl), the balanced chemical equation is:

[tex]Na_2CO_3 + 2HCl = > 2NaCl + H_2O + CO_2[/tex]

In an aqueous solution, however, both sodium carbonate and hydrochloric acid dissociate into ions.

As a result, the net ionic equation for the reaction will only include the species that change chemically. The net ionic equation is as follows:

[tex]CO_3^{2-} (aq) + 2H^{+} (aq) = > H_2O (l) + CO_2 (g)[/tex]

Carbonate ions from sodium carbonate react with hydrogen ions from hydrochloric acid to form water and carbon dioxide gas, as shown by this net ionic equation.

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When the volume of a closed vessel containing water and its vapor at equilibrium, H2O(l) + heat +H2O(g), is decreased... A. No change occurs B. In order to restore equilibrium, more liquid water evaporates C. In order to restore equilibrium, water vapor is heated up, absorbing the excess heat D. None of the above

Answers

When the volume of a closed vessel containing water and its vapor at equilibrium ([tex]H_{2}O[/tex](l) + heat ↔ [tex]H_{2}O[/tex](g)) is decreased, the correct answer is:
B. In order to restore equilibrium, more liquid water evaporates.

How does a system attain equilibrium?

When the volume of a closed vessel containing water and its vapor at equilibrium, the system will try to restore equilibrium. If the volume is decreased, the system will try to increase the concentration of water vapor to restore equilibrium. When the volume decreases, the pressure inside the closed vessel increases.

According to Le Chatelier's Principle, the system will respond by shifting the equilibrium to the side with fewer gas particles to reduce the pressure. In this case, the system will shift toward the liquid water side, causing more liquid water to evaporate and restore equilibrium.

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calculate the ph of a solution that results from mixing 44.3 ml of 0.24 m dimethylamine ((ch3)2nh) with 34.3 ml of 0.14 m (ch3)2nh2cl. the kb value for (ch3)2nh is 5.4 x 10-4.

Answers

The pH of the resulting solution is 10.50 that results from mixing 44.3 ml of 0.24 m dimethylamine ((ch3)2nh) with 34.3 ml of 0.14 m (ch3)2nh2cl. the kb value for (ch3)2nh is 5.4 x 10-4.

To calculate the pH, we need to first calculate the concentration of the resulting solution using the following formula: [tex]c1v1 + c2v2 = c3v3[/tex]

where c1 and v1 are the concentration and volume of dimethylamine, c2 and v2 are the concentration and volume of dimethylammonium chloride, and c3 and v3 are the concentration and volume of the resulting solution.

After calculating the concentration of the resulting solution, we can use the Kb value to calculate the pOH, and then use the formula pH + pOH = 14 to obtain the pH.

In this specific case, the pH is 10.50, indicating that the solution is slightly basic.

The mixing of dimethylamine and dimethylammonium chloride generates an equilibrium reaction between the two compounds. The resulting solution is a buffer solution that can resist changes in pH. The Kb value for dimethylamine can be used to calculate the concentration of hydroxide ions in the solution.

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if the electron cloud of a hydrogen atom was enlarged to the size of a sports statium, how large would the proton in the nucleus be?

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If the electron cloud of a hydrogen atom was enlarged to the size of a sports stadium, the proton in the nucleus would still be extremely small in comparison.

The diameter of a typical sports stadium is on the order of hundreds of meters to a kilometer, whereas the diameter of a hydrogen atom is about 0.1 nanometers (nm). This means that the size of the hydrogen atom compared to the stadium would be roughly analogous to the size of a pea compared to the stadium.

The proton in the nucleus of a hydrogen atom is even smaller, with a diameter of about 1.7 femtometers (fm) or 0.0000000000017 meters. This means that the size of the proton compared to the hydrogen atom would be roughly analogous to the size of a grain of sand compared to a pea.

Therefore, even if the electron cloud of a hydrogen atom were enlarged to the size of a sports stadium, the proton in the nucleus would still be incredibly small in comparison.

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Select the reagent for the following reaction. phenyl acetate ----> ? N-phenylacetamide. O Acid halide O Anhydride O Ester O Amide O Alcohol O Amine O Carboxylic acid or carboxylate (the conjugate base of carboxylic acid)

Answers

To convert phenyl acetate to N-phenylacetamide, you should use an amine as the reagent.

This reaction involves nucleophilic acyl substitution, where the amine will replace the ester group in phenyl acetate, resulting in the formation of N-phenylacetamide.

Here's the step-by-step mechanism for the conversion of phenyl acetate to N-phenylacetamide:

Nucleophilic attack: An amine, which acts as the nucleophile, attacks the carbonyl carbon of the phenyl acetate. The nitrogen atom in the amine donates its lone pair of electrons to the carbonyl carbon, forming a tetrahedral intermediate.

Elimination of alcohol: The tetrahedral intermediate formed in step 1 is unstable and undergoes elimination of the alcohol (methanol or ethanol), which was originally attached to the carbonyl carbon of phenyl acetate. This leads to the formation of an acyl-amine intermediate.

Rearrangement: The acyl-amine intermediate undergoes rearrangement, where the alkyl or aryl group originally attached to the carbonyl carbon (phenyl group in this case) migrates to the nitrogen atom of the amine, resulting in the formation of N-phenylacetamide.

Deprotonation: The resulting N-phenylacetamide may exist in its protonated form. To obtain the neutral form of N-phenylacetamide, the compound may be treated with a base, which can deprotonate the amide nitrogen, resulting in the formation of N-phenylacetamide.

The overall reaction can be represented by the following chemical equation:

Phenyl acetate + Amine → N-phenylacetamide + Alcohol

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Rank the following bonds from highest to lowest polarity.
a. O-Cl
b. S-Br
c. C-P

Answers

The bonds are as follows, listed from highest to lowest polarity:

b. S-Br > c. C-P > a. O-Cl

Calculation-

The atoms forming the bonds have electronegativities that are

[tex]O = 3.44Cl = 3.16S = 2.58Br = 2.96C = 2.55P = 2.19a. O-Cl bond: \\\\344 - 3.16 = 0.28b. S-Br bond: 2.96 - 2.58 = 0.38c. C-P bond: 2.55 - 2.19 = 0.36[/tex]

What does polarity in chemistry actually mean?

Polarity in chemical bonding is the distribution of electrical charge among the atoms linked by the bond. For instance, the chlorine atom is slightly negatively charged while the hydrogen atom in hydrogen chloride is slightly positively charged.

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what is the usable free energy (per mol) for transduction when nadh oxidizes and 1/2 o2 reduces? 220 kJ/mol. True or false?

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The statement "the usable free energy (per mol) for transduction when NADH oxidizes and 1/2 O2 reduces is 220 kJ/mol" is very close to the actual value, but not entirely accurate. The correct value is -219.5 kJ/mol.

The reaction you are referring to is the oxidation of NADH and the reduction of oxygen to form water. The overall reaction is:

NADH + 1/2 O2 -> NAD+ + H2O

The standard free energy change (ΔG°') for this reaction is -219.5 kJ/mol of NADH. Therefore, the maximum amount of usable free energy that can be obtained from the oxidation of NADH and the reduction of oxygen is 219.5 kJ/mol.

So, the statement "the usable free energy (per mol) for transduction when NADH oxidizes and 1/2 O2 reduces is 220 kJ/mol" is very close to the actual value, but not entirely accurate. The correct value is -219.5 kJ/mol.

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According to this balanced equation, how many grams of water (H₂O) form in this reaction? KOH 56.11 g HCI 36.46 g A. 167.12 grams OB. 94.20 grams C. 54.90 grams OD. 18.02 grams KCI 74.55 g H₂O ? SUBMIT​

Answers

The balanced chemical equation for the reaction between KOH and HCl is:

KOH + HCl -> KCl + H2O

From the equation, we can see that 1 mole of KOH reacts with 1 mole of HCl to produce 1 mole of water.

To determine the amount of water formed, we first need to calculate the number of moles of HCl and KOH used in the reaction:

moles of HCl = mass / molar mass = 36.46 g / 36.46 g/mol = 1.0 mol
moles of KOH = mass / molar mass = 56.11 g / 56.11 g/mol = 1.0 mol

Since the reaction is 1:1 between KOH and HCl, we know that 1.0 mol of water is formed.

To calculate the mass of water formed, we can use the molar mass of water, which is 18.02 g/mol:

mass of water = moles of water x molar mass of water = 1.0 mol x 18.02 g/mol = 18.02 g

Therefore, the answer is OD. 18.02 grams.

Calculate the wavelength of visible light having a frequency of 4.37 x 1014s-1.
A) 12.0 nm
B) 343 nm
C) 686 nm
D) 674 nm
E) none of the above

Answers

The wavelength of visible light with a frequency of 4.37 x [tex]10^{14}[/tex] s^-1 is approximately 686 nm (Option C).

How to calculate the wavelength of light?

To calculate the wavelength of visible light with a frequency of 4.37 x [tex]10^{14}[/tex] s^-1, you can use the formula:
Wavelength (λ) = Speed of light (c) / Frequency (f)

The speed of light (c) is approximately 3.0 x [tex]10^{8}[/tex] m/s.

Plug in the given frequency (f) into the formula:

λ = (3.0 x [tex]10^{8}[/tex] m/s) / (4.37 x [tex]10^{14}[/tex] s^-1)
λ ≈ 6.86 x [tex]10^{-7}[/tex] m

To convert the wavelength to nanometers (nm), multiply by [tex]10^{9}[/tex]:
λ ≈ 6.86 x [tex]10^{-7}[/tex] m * [tex]10^{9}[/tex] nm/m = 686 nm

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of the molecules sif4 and sibr4 , which has bonds that are more polar? view available hint(s)for part b sif4 sibr4

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SiF4 has a more polar bond than SiBr4 due to the higher electronegativity .

which molecule between SiF4 and SiBr4 has more polar bonds?

The polarity of a bond depends on the difference in electronegativity between the atoms involved. Silicon has an electronegativity of 1.9, while fluorine and bromine have electronegativities of 3.98 and 2.96, respectively.

The bond in SiF4 is more polar because the difference in electronegativity between silicon and fluorine (2.08) is greater than that between silicon and bromine (1.06). The polar nature of SiF4 makes it a good candidate for use in various chemical reactions and industrial processes.

Understanding the polarity of molecules is crucial in predicting their behavior in chemical reactions and in designing new materials with desired properties

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the radial part of a hydrogen 2p wave function expectiation valueR2p(r)=1^24(1/a0)3/2(r/a0)e-r/2a0. a. Draw schematically, the R2p radial wave functions as a function of r/ao. b. Locate the maximum of the radial electron density distribution. c. Calculate the expectation value for the distance between electron and nucleus.

Answers

a. The R2p radial wave functions as a function of r/ao can be represented with a bell-shaped curve.

b. The maximum of the radial electron density distribution occurs at the peak of the curve.

c. The expectation value for the distance between electron and nucleus is 9/8 times the Bohr radius (a0).

a. The R2p radial wave function as a function of r/ao can be represented schematically as a bell-shaped curve with a peak at r/ao = 2. This means that the probability of finding the electron at a distance of 2 times the Bohr radius (a0) from the nucleus is the highest.

b. The maximum of the radial electron density distribution occurs at the peak of the bell-shaped curve, which is at r/ao = 2. At this distance, the electron is most likely to be found.

c. To calculate the expectation value for the distance between electron and nucleus, we need to use the formula:

< r > = ∫0∞ rR2p(r)^2 dr

Substituting the given wave function, we get:

< r > = ∫0∞ r(1/24)(1/a0)3/2(r/a0)e^(-r/a0) dr

This integral can be solved using integration by parts, and the final result is:

< r > = 9/8 a0

Therefore, the expectation value for the distance between the electron and nucleus is 9/8 times the Bohr radius (a0).

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Part C Give the names of the anion in each of the following compounds CaO, Na2SO4, KCIO4, Fe (NO3) 2, Cr (OH) 3 Spell out the names of the anions separated by commas.

Answers

The anion in each of the following compounds CaO, Na₂SO₄, KClO₄, Fe(NO₃)₂, Cr(OH)₃ is oxide (O²⁻), sulfate (SO₄²⁻), perchlorate (ClO₄⁻), nitrate (NO₃⁻), and hydroxide (OH⁻), respectively.

An anion is a negatively charged ion that is formed when an atom gains one or more electrons. An atom typically gains electrons to achieve a more stable electron configuration, which is often accomplished by filling or partially filling its outermost electron shell. Anions are named based on the element they are derived from and end in the suffix "-ide."

Calcium oxide (CaO) has the anion oxide (O²⁻), sodium sulfate (Na₂SO₄) has the anion sulfate (SO₄²⁻), potassium perchlorate (KClO₄) has the anion perchlorate (ClO₄⁻), iron(II) nitrate (Fe(NO₃)₂) has the anion nitrate (NO₃⁻), and chromium(III) hydroxide (Cr(OH)₃) has the anion hydroxide (OH⁻).

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Arrange the given compounds in order of their increasing bond length: HCl, HI, HBr, HF. Explain the order.

Answers

Therefore, the order of increasing bond length is HF < HCl < HBr < HI.

How to find the order of Bond Length in compounds?

To arrange the given compounds HCl, HI, HBr, and HF in order of their increasing bond length, consider the size of the halogen atoms involved. Bond length increases with the size of the atoms involved in the bond.

1. HF: Fluorine is the smallest halogen, resulting in the shortest bond length.
2. HCl: Chlorine is larger than fluorine, so the bond length in HCl is longer than HF.
3. HBr: Bromine is larger than chlorine, leading to a longer bond length in HBr compared to HCl.
4. HI: Iodine is the largest halogen in the list, so HI has the longest bond length.

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Using the VSEPR model, the electron pair arrangement around the central atom in BrF4 is А linear B. trigonal planar C tetrahedral D. trigonal bipyramidal E. octahedral

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Using the VSEPR model, the electron pair arrangement around the central atom in BrF4 is D. trigonal bipyramidal.

In the VSEPR model, the electron pair geometry is determined by the number of bonding pairs and lone pairs surrounding the central atom. In BrF4, the central atom is bromine (Br), which is bonded to four fluorine (F) atoms. Additionally, there is one lone pair of electrons on the bromine atom.

Considering that bromine has five electron pairs (four bonding pairs and one lone pair), this results in a trigonal bipyramidal geometry. In this arrangement, the lone pair occupies an equatorial position, while the four fluorine atoms form two axial and two equatorial positions, with the axial positions being 180° apart and the equatorial positions being 120° apart. This electron pair geometry minimizes electron repulsion and leads to a stable molecular structure.

Therefore, the correct answer is D. trigonal bipyramidal.

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In BrF4, the central atom is Br (Bromine).
Position around the central atom in BrF4?

The VSEPR model, the electron pair arrangement around the central atom in BrF4 is D. trigonal bipyramidal.
Identify the central atom: In BrF4, the central atom is Br (Bromine).
Determine the number of valence electrons: Br has 7 valence electrons and each F (Fluorine) has 7, making a total of 4 F atoms = 4 x 7 = 28. So, the total valence electrons = 7 (Br) + 28 (4 F atoms) = 35.
Calculate electron pairs: Divide the total valence electrons by 2 to find the electron pairs: 35/2 = 17.5. Since we can't have a fraction of an electron pair, it means there's one lone pair of electrons on the central atom (Br).
Determine the electron pair geometry: With 4 bonding pairs (F atoms) and 1 lone pair on the central atom (Br), we have a total of 5 electron pairs. This arrangement corresponds to a trigonal bipyramidal geometry in the VSEPR model.

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Part A Find the pH of a 0.130 M solution of a weak monoprotic acid having Ka= 1.0×10−5.
Part B Find the percent ionization of a 0.130 M solution of a weak monoprotic acid having Ka= 1.0×10−5.
Part C Find the pH of a 0.130 M solution of a weak monoprotic acid having Ka= 1.3×10−3.
Part D Find the percent ionization of a 0.130 M solution of a weak monoprotic acid having Ka= 1.3×10−3.
Part E Find the pH of a 0.130 M solution of a weak monoprotic acid having Ka= 0.13.
Part F Find the percent ionization of a 0.130 M solution of a weak monoprotic acid having Ka= 0.13.

Answers

Part A:

To find the pH of a 0.130 M solution of a weak monoprotic acid with Ka = 1.0×10-5, we can use the following equation:

Ka = [H+][A-]/[HA]

Where [H+] is the concentration of hydrogen ions, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid. Since the acid is monoprotic, the concentration of the acid is the same as the concentration of the initial solution.

We can set up an ICE table to find the concentration of each species:

HA + H20 ↔ H3O+ + A-

↔ H3O+ + A-I 0.130 M 0 M 0 M

↔ H3O+ + A-I 0.130 M 0 M 0 MC -x +x +x

↔ H3O+ + A-I 0.130 M 0 M 0 MC -x +x +xE 0.130-x x x

Substituting these values into the Ka expression, we get:

1.0×10^-5 = (x^2)/(0.130-x)

Solving for x using the quadratic formula, we get x = 3.162×10^-3 M. This is the concentration of [H+].

Taking the negative log of [H+], we get the pH:

pH = -log[H+] = -log(3.162×10^-3) = 2.50

Therefore, the pH of a 0.130 M solution of a weak monoprotic acid with Ka = 1.0×10-5 is 2.50

Part B:

To find the percent ionization of the weak acid, we can use the equation:

% Ionization = ([H+]/[HA]) × 100

% Ionization = ([H+]/[HA]) × 100From Part A, we found that [H+] = 3.162×10^-3 M and [HA] = 0.130 M, so:

% Ionization = ([H+]/[HA]) × 100From Part A, we found that [H+] = 3.162×10^-3 M and [HA] = 0.130 M, so:% Ionization = (3.162×10^-3/0.130) × 100 = 2.43%

Therefore, the percent ionization of a 0.130 M solution of a weak monoprotic acid with Ka = 1.0×10−5 is 2.43%.

Part C:

To find the pH of a 0.130 M solution of a weak monoprotic acid with Ka = 1.3×10^-, we can use the same method as in Part A.

Setting up an ICE table:

HA + H2O ↔ H3O+ + A-

HA + H2O ↔ H3O+ + A-I 0.130 M 0 M 0 M

HA + H2O ↔ H3O+ + A-I 0.130 M 0 M 0 MC -x +x +x

HA + H2O ↔ H3O+ + A-I 0.130 M 0 M 0 MC -x +x +xE 0.130-x x x

Substituting these values into the Ka expression, we get:

1.3×10^-3 = (x^2)/(0.130-x)

Solving for x, we get x = 0.0361 M. This is the concentration of [H+].

Taking the negative log o [H+], we get the pH:

pH:pH = -log[H+] = -log(0.0361) = 1.44

Therefore, the pH of a 0.130 M solution of a weak monoprotic acid with Ka = 1.3×10^-3 is 1.44.

Ka = 1.3×10^-3 is 1.44.Part D:

To find the percent ionization of the weak acid, we can use the same equation as in Part B:

% Ionization = ([H+]/[HA]) × 100

% Ionization = ([H+]/[HA]) × 100From Part C, we found that [H+] = 0.0361 M and [HA] = 0.130 M, so:

% Ionization = ([H+]/[HA]) × 100From Part C, we found that [H+] = 0.0361 M and [HA] = 0.130 M, so:% Ionization = (0.0361/0.130) × 100 = 27.8%

Therefore, the percent ionization of a 0.130 M solution of a weak monoprotic acid with Ka = 1.3×10^-3 is 27.8%.

Part E:

To find the pH of a 0.130 M solution of a weak monoprotic acid with Ka = 0.13, we can use the same method as in Part A

Setting up an ICE table:

HA + H2O ↔ H3O+ + A-

HA + H2O ↔ H3O+ + A-I 0.130 M 0 M 0 M

HA + H2O ↔ H3O+ + A-I 0.130 M 0 M 0 MC -x +x +x

HA + H2O ↔ H3O+ + A-I 0.130 M 0 M 0 MC -x +x +xE 0.130-x x x

Substituting these values into the Ka expression, we get:

0.13 = (x^2)/(0.130-x)

Solving for x, we get x = 0.191 M. This is the concentration of [H+].

Taking the negative log of [H+] we get the pH:

Therefore, the pH of a 0.130 M solution of a weak monoprotic acid with Ka = 0.13 is 0.72.

Part F:

To find the percent ionization of the weak acid, we can use the same equation as in Part B:

% Ionization = ([H+]/[HA]) × 100

% Ionization = ([H+]/[HA]) × 100From Part E, we found that [H+] = 0.191 M and [HA] = 0.130 M, so:

% Ionization = ([H+]/[HA]) × 100From Part E, we found that [H+] = 0.191 M and [HA] = 0.130 M, so:% Ionization = (0.191/0.130) × 100 = 147%

Note that the percent ionization is greater than 100%. This is because the acid is relatively strong (compared to the previous examples) and ionizes to a greater extent.

Note that the percent ionization is greater than 100%. This is because the acid is relatively strong (compared to the previous examples) and ionizes to a greater extent.Therefore, the percent ionization of a 0.130 M solution of a weak monoprotic acid with Ka = 0.13 is 147%.

Formic acid, HCOOH, ionizes in water according ot the following equation. The equilibrium constant is K = 1.8x10-4.HCOOH(aq)+H_{2}O(l)\rightleftharpoons HCOO^{-}(aq)+H_{3}O^{+}(aq)Calculate the equilibrium concentration of H3O+ in a 0.985 M solution_____ M

Answers

The first step to calculate the equilibrium concentration is to write the balanced equation for the ionization of formic acid in water.

How do you go about solving this problem?

The equation for this reaction is:

HCOOH + H₂O ⇌ HCOO⁻ + H3O⁺

Next, we can define the initial, change, and equilibrium concentrations of HCOOH, HCOO⁻, and H3O⁺:

Let x be the equilibrium concentration of H3O⁺ and HCOO⁻.

Initial concentration of HCOOH = 0.985 M

Initial concentration of H₂O is much larger than the initial concentration of HCOOH, so we can assume that the concentration of H₂O does not change significantly during the reaction.

   Initial concentration of HCOO⁻ and H3O+ = 0 M

   Change in concentration of HCOOH = -x

   Change in concentration of HCOO⁻= +x

   Change in concentration of H3O⁺ = +x

   Equilibrium concentration of HCOOH = 0.985 - x M

   Equilibrium concentration of HCOO⁻ = x M

   Equilibrium concentration of H3O⁺ = x M

We can now use the equilibrium constant expression to solve for x:

K = [HCOO⁻][H3O⁺]/[HCOOH]

1.8 × 10⁻⁴ = x² / (0.985 - x)

Since x is much smaller than 0.985 (the initial concentration of HCOOH), we can assume that the equilibrium concentration of HCOOH is approximately equal to the initial concentration of HCOOH. Therefore:

0.985 - x ≈ 0.985

Substituting this approximation into the equilibrium constant expression, we get:

1.8 × 10⁻⁴ = x² / 0.985

x²= 1.8 × 10⁻⁴ × 0.985

x² = 1.773 × 10⁻⁴

x = 0.0133 M

Therefore, the equilibrium concentration of H3O⁺ in a 0.985 M solution of formic acid is 0.0133 M.

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What is the mass of 4.18 x 1020 molecules of carbon monoxide

Answers

Answer:

0.0194 g or 19.4 mg

Explanation:

First convert the number of molecules into moles by a conversion factor 6.02 x 10^23 molecules = 1 mol

4.18x10^20 molecules x (1 mol / 6.02x10^23 molecules) = 6.94x10^-4 moles

Then the Molar Mass is 12.01 + 16.00 = 28.01 g / mol

6.94 x 10^-4 moles CO x (28.01 g /mol) = 0.0194 g = 19.4 mg

Is this the correct lewis dot structure for PO₃¹⁻?

Answers

Answer:

No

Explanation:

theoretical yield of sodium hypochloriteoxidation of 4-tert-butylcyclohexanol

Answers

The result will be the theoretical yield of sodium hypochlorite for the given amount of 4-tert-butylcyclohexanol used in the reaction stoichiometry.

To find the theoretical yield of sodium hypochlorite oxidation of 4-tert-butylcyclohexanol, you need to first calculate the amount of 4-tert-butylcyclohexanol used in the reaction and then use stoichiometry to determine the maximum amount of sodium hypochlorite that can be produced.
Assuming the reaction goes to completion, the theoretical yield is the maximum amount of product that can be produced based on the amount of limiting reagent used. In this case, 4-tert-butylcyclohexanol is the limiting reagent.
The balanced equation for the reaction is:
4-tert-butylcyclohexanol + 4NaOCl ⇒ 4-tert-butylcyclohexyl chloroformate + 4NaCl + 4H₂O
From the equation, we can see that for every 1 mole of 4-tert-butylcyclohexanol used, 1 mole of sodium hypochlorite is consumed. Therefore, we can calculate the amount of 4-tert-butylcyclohexanol used by dividing the given mass by its molar mass.
Once we have the amount of 4-tert-butylcyclohexanol used, we can use stoichiometry to determine the maximum amount of sodium hypochlorite that can be produced. To do this, we multiply the amount of 4-tert-butylcyclohexanol used by the stoichiometric ratio of sodium hypochlorite to 4-tert-butylcyclohexanol, which is 1:1. However, it's important to note that the actual yield may be less than the theoretical yield due to side reactions, incomplete reactions, and other factors.

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The result will be the theoretical yield of sodium hypochlorite for the given amount of 4-tert-butylcyclohexanol used in the reaction stoichiometry.

To find the theoretical yield of sodium hypochlorite oxidation of 4-tert-butylcyclohexanol, you need to first calculate the amount of 4-tert-butylcyclohexanol used in the reaction and then use stoichiometry to determine the maximum amount of sodium hypochlorite that can be produced.
Assuming the reaction goes to completion, the theoretical yield is the maximum amount of product that can be produced based on the amount of limiting reagent used. In this case, 4-tert-butylcyclohexanol is the limiting reagent.
The balanced equation for the reaction is:
4-tert-butylcyclohexanol + 4NaOCl ⇒ 4-tert-butylcyclohexyl chloroformate + 4NaCl + 4H₂O
From the equation, we can see that for every 1 mole of 4-tert-butylcyclohexanol used, 1 mole of sodium hypochlorite is consumed. Therefore, we can calculate the amount of 4-tert-butylcyclohexanol used by dividing the given mass by its molar mass.
Once we have the amount of 4-tert-butylcyclohexanol used, we can use stoichiometry to determine the maximum amount of sodium hypochlorite that can be produced. To do this, we multiply the amount of 4-tert-butylcyclohexanol used by the stoichiometric ratio of sodium hypochlorite to 4-tert-butylcyclohexanol, which is 1:1. However, it's important to note that the actual yield may be less than the theoretical yield due to side reactions, incomplete reactions, and other factors.

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Question 7 of 30
What is the cell potential of an electrochemical cell that has the half-reactions
shown below?
Ag* + e → Ag
Fe→ Fe³+ + 3e

Answers

The difference between the two half-reactions' standard reduction potentials is what determines the cell potential of an electrochemical cell. The first half-reaction's standard reduction potential is 0.799V, and the second half-reaction's standard reduction potential is -0.771V.

The electrochemical cell's cell potential is therefore equal to the difference between these two readings, which is equal to 0.799V + (-0.771V) = 0.028V. The cell potential, which indicates the greatest amount of energy the cell is capable of producing, is a crucial electrochemical metric.

It is a gauge of the cell's potential energy and is determined by the difference between the standard reduction potentials of the two half-reactions. The more energy that can be created by cells depends on their cell potential.

The capacity of the cell to create energy increases with its potential. The electrochemical cell in the example can only generate a negligibly small quantity of energy, as indicated by its cell potential of 0.028V.

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