What is the ph at the equivalence point in the titration of a 25. 6 ml sample of a 0. 397 m aqueous hydrofluoric acid solution with a 0. 406 m aqueous potassium hydroxide solution?
the pH at the equivalence point in the titration of 25.6 ml is.
=12×14+12×3.74+12log 0.1=8.37.
What does the ph at equivalency point formula mean?The weak acid salt hydrolysis determines the pH at the equivalence point in the titration of weak acid with strong base.As a result, we must determine the pKb of the conjugated base, compute the concentration of OH- beginning from there, and then utilize the pH=14-pOH formula.
Why is pH of the equivalency point 7?The pH at the equivalence point is more than 7 in a weak acid/strong base titration.This is because the mixture contains water, the neutral cation of a strong base, and the anion of a weak acid (a base).
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the bonding energy of the 1s electron in nitrogen is 409.9 ev. what wavelength of light is required to remove this core electron from the atom?
E=2.1781018J is the ratio for an atom energy (n2Z2). wavelength of light required to shift an electron in a hydrogen atom between level n=1 to n=2.
What are frequencies and wavelengths?The wavelength, which will also apply to troughs, is the separation between two wave crests. The frequency is measured in frames a second (Hz), which is the quantity of vibrations that cross a specific area in a second (Hertz).
What does one wavelength go by?When wavelength is expressed in metres, 1/ represents the amount of waves in a wave train that can be discovered in a duration of one metre, or for the number in a height of one centimeter if wavelength is expressed in centimeters. Its amplitude of the wave of the spectra line is the name given to this figure.
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If The Bond Angle Between Two Adjacent Hybrid Orbitals Is 180 Hybridization?
A. Sp3
B. Sp
C. Sp2
D. Sp3d
Hybridization is Sp2 if the bond angle between two adjacent hybrid orbitals is 180 degrees.
What exactly is an orbital?
A space object that orbits another space object looks to be doing so. A spacecraft that orbits the earth is called a satellite. One option is a natural satellite that neither matches the Earth nor the moon. Many different countries have moons as satellites in their orbits. An additional option is a man-made satellite, such as the Space Stations.How do orbitals get started?
When many atoms combine chemically to form a molecule, the atomic orbitals are combined into molecular orbitals, dictating the positions of the electrons by the entire molecule. The electrons of the constituent atoms are located in the molecular orbitals. Each orbital has two electrons with different spins. The region of space where an electron resides in an atom is called its orbital.To know more about Orbitals click:
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In a single displacement reaction between al2s3 and li, what products will form and why?.
Answer: Li2S and Al because metals replace metals
Explanation:
The chemical reaction between Al₂S₃ and lithium is a single displacement reaction which forms products of lithium sulfide Li₂S and Al.
What is a chemical reaction?Chemical reactions are defined as reactions which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.
There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical reaction there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical reactions:
1) inorganic reactions
2)organic reactions
3) biochemical reactions
During chemical reactions atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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c Shazad's pebble has a mass of 90 g and a volume of 30 cm³. What is its density?
Answer:
Density = 3 g/cm³
Explanation:
Density is a ratio which compares an object's mass per every 1 unit volume. Grams is a unit of mass and cm³ is a unit of volume. Since you have been given values for both a mass and volume, you can use them to determine the density.
Density = g/cm³ <----- Density units
Density = 90 g / 30 cm³ <----- Insert values
Density = 3 g / 1 cm³ <----- Simplify
Density = 3 g/cm³
draw the major product formed when the epoxide reacts with methanol in the presence of sulfuric acid. use wedge‑and‑dash bonds, including hydrogens at each stereogenic center, to show the stereochemistry of the product.
The major product of the reaction is (2S,3R)-3-methoxy - 3-methylpentan-2-ol
Epoxide reacts with methanol in the presence of sulfuric acid.
In this chemical reaction, methanol act as nucleophile and sulfuric acid act as catalyst.
What are Epoxides?
Epoxides are a type of cyclic ether in which a three-membered ring is formed by a oxygen atom bonded to two adjacent carbon atoms. They are also known as oxiranes. Epoxides are used in a variety of applications, including as chemical intermediates, catalysts, and as raw materials for a range of products.
What is sulfuric acid?
Sulfuric acid is a strong, corrosive acid that is used in a variety of industrial applications. It is also known as battery acid, as it is used in car batteries to facilitate a chemical reaction. Sulfuric acid is colorless and odorless, and is composed of two hydrogen atoms, one sulfur atom, and four oxygen atoms.
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Scientists are studying fertilizers to help grass grow in southern California. Fertilizer is any substance that can be added to soil to help plants grow in it. In other words, fertilizer makes soil more fertile. The scientists set up different plots of land that all use the same type of soil and grass seed, but they use different types of fertilizer in each plot. Scientists then measure the grass growth in the different soils over time.
How should scientists set up the control group in this experiment?
a plot with grass seed but no fertilizer in the soil
a plot with grass seed and many types of fertilizer in the soil
a plot without any grass seed or any fertilizer in the soil
a plot without any grass seed but with fertilizer in the soil
Answer:
The corrrect answer will be option-A.
Explanation:
A scientific experiment contains two types of groups: the control and the experimental groups. The control group in any scientific experiment is the sample which does not receive the variable we need to test which is provided in the experimental groups.
In the given question, the scientist wanted to study the effect of fertilizers on the growth of the grass. so the parameter (variable) to be studied is fertilizer. The experimental samples are provided with different concentration of the fertilizer but the control sample will not receive the fertilizers as the control sample provides the base or reference to the experimental group to increase the accuracy of the results obtained.
Thus, option-A is the correct answer.
Solid lithium metal and diatomic nitrogen ga react pontaneouly to form a olid product. Give the balanced chemical equation (including phae) that decribe thi reaction. Indicate the phae uing abbreviation (), (l), or (g) for olid, liquid, or ga, repectively
The balanced chemical equation for the reaction is as follows:
6 Li[s] + [tex]N_{2}[/tex][g] = 2[tex]Li_{3}[/tex]N[s]
Meaning of the reaction is that 6 moles of lithium reacts with nitrogen to form two moles of lithium nitride.
The product formed is:
Highly flammable and reactive chemical and a Dangerous fire and explosion hazard.
Lithium Nitride can affect you when breathed in and may be absorbed through the skin.
Contact can severely irritate and burn the skin and eyes. Breathing Lithium Nitride can irritate the nose and throat.
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h2o(s)→ h2o(l) physical or chemical changel
What is the average atomic mass of the element represented above
The average atomic mass of the element which is represented in the above diagram is 16.
What is meant by an element?An element is defined as a substance which cannot be split into simpler forms by ordinary chemical process. There are different categories of elements including the metals, nonmetals and metalloids.
That being said, the oxygen is a chemical element which belongs to group 6 and period 2 in the periodic table, has valence electron of 6, and an average mass of 16. In addition to this, oxygen is a metal. Some few examples of other chemical elements include:
Hydrogen, HHelium, HeLithium, LiBeryllium, BeBoron, BCarbon, CNitrogen, NOxygen, OFluorine, FNeon, NeSodium, NaMagnesium, MgAluminum, AlSo therefore, it can be deduced from the explanation given above that oxygen is a chemical element which is diatomic.
Complete question:
What is the average atomic mass of the element represented above
a. 8
b. 16
c. 32
d. 64
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a sammple 0f 0.010 mole of oxygen gas is confine at 127c and .80 atmospheres. what would be the pressure of this sample at 27c and thw ame volume
The pressure of this sample at 27° c and at the same volume is calculated to be 0.6 atm.
What is the Gay-Lussac equation?Law of Gay-Lussac states that pressure of a given mass of gas varies directly with Kelvin temperature when the volume is constant.
Given that the volumes of the two states are equal. At constant volume, we use the Gay-Lussac equation:
As, P₁/T₁ = P₂/T₂
Given P1= 0.8 , T1= 127°
and T2= 27°
Now, (0.8)/(127+273) = (P₂)/(27+273)
We get, P₂ = 0.6 atm
The pressure of this sample at 27° c and at same volume is 0.6 atm.
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You will be given 4.6x10^3 mg of Sodium Chloride, how many atoms of NaCl do I have?
The total number of molecules that are present in 4.6×[tex]10^{3}[/tex] mg of NaCl is 0.47×[tex]10^{23}[/tex]
Atomic masses:
Na=23 , Cl=35.5
The molar mass of NaCl=58.5
1gm of NaCl contains=1/58.5 moles of NaCl
And,
1gm of NaCl contains=1/58.5×6.022×[tex]10^{23}[/tex] molecules of NaCl
4.6x[tex]10^{3}[/tex] mg =(4.6x[tex]10^{3}[/tex]x[tex]10^{-3}[/tex] gm) of NaCl contains= [tex]\frac{1}{58.5}[/tex] ×6.022×[tex]10^{23}[/tex]×4.6
=0.017×27.70×[tex]10^{23}[/tex]
=0.47×[tex]10^{23}[/tex]
Therefore the total number of molecules present in 4.6×[tex]10^{3}[/tex] mg NaCl is 0.47×[tex]10^{23}[/tex]
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A reaction at 32.0 °C evolves 526. mmol of sulfur tetrafluoride gas.
Calculate the volume of sulfur tetrafluoride gas that is collected. You can assume the pressure in the room is exactly 1 atm.
Round your answer to 3 significant digits.
The volume of sulfur tetrafluoride gas that is collected is 13.17L.
How to calculate volume?The volume of an ideal gas can be calculated using the following ideal gas equation;
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
n = number of moles (mol)
T = temperature (K)
R = gas law constant
According to this question, a reaction occurs at 32.0°C and evolves 526mmol of sulfur tetrafluoride gas. The volume of sulfur tetrafluoride gas collected assuming the pressure in the room is exactly 1 atm can be calculated as follows:
1 × V = 0.526 × 0.0821 × 305
V = 13.17L
Therefore, 13.17L is the volume of the gas.
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Identifying isotopes helpp
Isotopes are any of two or more forms of an element where the atoms have the same number of protons, but a different number of neutrons within their nuclei. Thus, isotopes have the same atomic number but a different mass number.
In an atom, there are three components called subatomic particles as follows:
ProtonElectronNeutronIn a neutral atom, the number of protons, which is the atomic number, equate the number of electrons.
According to this question, the transparent subatomic particle inside the atom's nucleus is proton while the blue colored particle is the neutron.
In atom A, there are 3 protons, hence the atomic number of atom A is 3. However, in atom B, the number of protons and neutrons are 4 and 3 respectively, hence, the mass number i.e. protons + neutrons is 7.
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In a spectrophotometer, both absorbance and transmittance indicate choose. Passing through a sample. A high absorbance corresponds to a choose. Transmittance.
If the solution absorbs large amount of light, then it will transmit very less amount of light. Therefore, A high absorbance corresponds to a Low transmittance.
What is spectrophotometer?
A spectrophotometer is a device that accurately measures electromagnetic energy at specific wavelengths of light. It uses properties of light and energy to identify colors and determine the amount of each color in a ray. The two main components of a spectrophotometer are the spectrometer and the photometer.
Spectrometer: A spectrometer sends a straight beam of light through a lens to a prism, which splits it into individual wavelengths. A wavelength selector then filters only the specified wavelengths and sends them to the photometer.
Photometer: A photometer is a piece of device that detects the number of photons absorbed and transmits that measurement to a digital readout.
Therefore, A high absorbance corresponds to a Low transmittance.
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When a 6.50 g sample of solid NaOH dissolves in 100.0g of water in a coffee-cup calorimeter, the temperature rises from 21.6°C to 37.8°C. Calculate the ∆H (in kJ/mol NaOH) for the solution process. (Assume the specific heat of the solution formed is 4.18 J/g-K)
NaOH(s) ® Na+ (aq)+ OH–(aq)
Hello,
I hope you and your family are doing well!
To calculate the ∆H for the solution process of NaOH, you can use the equation:
∆H = q/n
where q is the heat absorbed or released during the process, and n is the number of moles of solute that are dissolved.
To find the heat absorbed or released during the process, you can use the equation:
q = m * C * ∆T
where m is the mass of the solvent (water), C is the specific heat of the solvent, and ∆T is the change in temperature of the solvent.
Substituting the given values into this equation gives us:
q = 100.0 g * 4.18 J/g-K * (37.8°C - 21.6°C) = 10,019 J
To find the number of moles of NaOH dissolved, you can use the molar mass of NaOH:
n = 6.50 g / 39.9968 g/mol = 0.1625 mol
Substituting these values into the equation ∆H = q/n gives us:
∆H = 10,019 J / 0.1625 mol = 61,726 J/mol
Converting this to kJ/mol gives us:
∆H = 61,726 J/mol / 1000 J/kJ = 61.726 kJ/mol
Therefore, the ∆H for the solution process of NaOH is approximately 61.726 kJ/mol.
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Happy Holidays & New Year!
How many moles of O are in 132.03 g of CO2? (molar mass = 44.01 g/mol)?
There are 3.00 molecules of CO2 in 132.03 grams of CO2.
What is mass?Mass is quantitative measure of interia a fundamental quantity of all matter.
Mass of CO2 = 132.03 grams
Number of molecules of CO2 = ?
Molar mass of CO2 = ?
For the molar mass of CO2: Atomic mass of Carbon = 12; Oxygen = 16
= 12 + (16 x 2)
= 12 + 32 = 44g/mol
Apply the formula:
number of molecules = (mass in grams/molar mass)
N = (132.03 grams/44g/mol)
N = 3.00 molecules
Thus, there are 3.00 molecules of CO2 in 132.03 grams of CO2.
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When an atom X of an element in Group 1 reacts to become X+
When an atom X of an element in Group 1 reacts to become X+, number of filled energy levels decreases. The correct option is D.
What are energy levels and how to explain this?An atom's electrons typically fill all of the lowest energy levels first, followed by the higher ones. The electrons are in the lowest energy state possible thanks to this filling order.
Atom X will lose an electron to become atom [tex]X^{+1}[/tex], since the atom is neutral and the electron is unit negatively charged. While the nonmetal picks up one or more electrons, the metal loses one or more. The amount of electrons lost is a function of the metal's position in the periodic table. Elements in group 1 lose one electron, while those in group 2 lose two. When one electron is lost, a positive charge results because there are more protons than electrons. With the negative charge, the opposite occurs.
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The complete question is:
When an atom X of an element in Group 1 reacts to become X+ -
A mass number of X increases.
B atomic number of X decreases.
C charge of the nucleus increases.
D number of filled energy levels decreases.
The particle accelerator with a circular path that smashes together particles to make new atoms and particles is called a
Question 28 options:
synchrotron.
mass spectrometer.
cyclotron.
linear particle accelerator.
Answer:
linear particle accelerator
based on the molar mass of nacl (58.44 g/mol) and on the count of the ions inside the unit cell, what is the mass (in grams) of nacl is in a unit cell.
Therefore, 0.25 moles of unit cells will be present in 58.5 g.
How many atoms make up a mole of sodium chloride?Therefore, 6.0231023 6.023 10 23 molecules make up 1 mole of NaCl. The total number of atoms in 1 mole of NaCl N a C l is twice Avogadro's number, or 6.0231023 6.023 10 23 because each molecule of the salt has two atoms (Na and Cl).
How can you determine an ion's mass?Similar to covalent compounds, the formula mass of an ionic compound is determined by adding the average atomic masses of all the atoms in the compound's formula.
Calculation:1 mole of NaCl
Avogadro's number, or 6.0231023
0.25 moles of unit cells will be present in 58.5 g.
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A newspaper started an online version of its paper 14 years ago. In a recent presentation to stockholders, the lead marketing executive stated, “The revenues for online ads are more than double that of the revenues for printed ads.”
Answer:
According to the graph, during year 14, revenue from online ads is approximately $4.2 million, while revenue from online ads has more than doubled revenue from printed ads (at least by year 14)
Both curves intersect between the seventh and eighth year, I would say around the middle of year 7, and both online ads and printed ads generated an approximate revenue of $2.2 million each
Explanation:
the______is a group that continues under normal conditions in an experiment
Answer:
The "control" is a group that continues under normal conditions in an experiment.
Explanation:
The control group regulates the experiment and serves as a reference point for changing variables.
2H2O2 → O2 + 2H2O
a. Single Displacement
b. Synthesis
c. Decomposition
d. Combustion
Which one of these is it?
Answer:
c. decomposition
Explanation:
it formula is splitting between O2 and 2H2O
which of these ions is more abundant in the interior of a resting neuron than in the fluid surrounding the neuron?
This indicates that the neuron's inside potential is 70 mV lower than its outside. At rest, the potassium ions inside the cell outnumber the sodium ions by a somewhat large margin.
Which of these ions is present in a resting neuron's interior in greater amounts?Potassium ions are kept at high concentrations inside neurons whereas sodium ions are kept at high quantities outside the cell.
The potassium and sodium cations can diffuse down their concentration gradients because the cell has leaky channels that allow them to do so.
For cells to operate normally, these variations are essential. Outside of the cell, sodium ions are far more common than within.
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A calorimeter is to be calibrated: 51. 203g of water at 55. 2c is added to a calorimeter containing 49. 783g of water at 23. 5c. After stirring and waiting for the system to equilibrate, the final temperature reached is 37. 6c. Calculate the calorimeter constant
According to the given statement The amount of heat that water absorbs is 878.64 J.
What is the calorimeter constant formula?Equation q = -CT, where C seems to be the calorimeter's heat capacity and T is the temp change, can be used to determine how much heat is released during the reaction. Since the combustion takes place at a fixed volume, the reaction's q is equal to E.
Briefing:Amount of water = m = 75.0 g
Specific heat capacity of water = c = 4.184 J /g⁰C
Initial temperature of water = T = 23.0⁰C
Final temperature of water = T' = 20.2⁰C
The phrase for how much heat water absorbs is presented below.
q = mcΔT
q = 75.0 g * 4.184 J /g⁰C * (23.0 - 20.2)⁰ C
q = 878.64
The amount of heat that water absorbs is 878.64 J
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if the half-life of a radioactive element is 18 days, what percentage of the original sample would be left after 108 days?
Half life Of Radioactive Element is 18 days
Percentage of original sample remained after 108 days is 1.5625%
What is Half Life of Reaction?The amount of time needed for a reactant to achieve half of its starting concentration or pressure is known as the half-life of a reaction. The half-life for a first-order reaction is concentration-independent and stable over time.
It is denoted by the symbol ‘t1/2’ and is usually expressed in seconds.
Calculation:Given;
t 1/2 = 18 days;
t = 108 days;
Amount of remaining radioactive element
R = [tex]\frac{Ro}{2^n}[/tex], where n = [tex]\frac{t}{t1/2}[/tex]
⇒n= 108/18
n= 6;
so,
[tex]\frac{R}{Ro}[/tex] = [tex]\frac{1}{2^6}[/tex]
= 0.015625
⇒ Percentage of original sample remained , [tex]\frac{R}{Ro}[/tex] × 100 = 1.5625 %
Half life Of Radioactive Element is 18 days
Percentage of original sample remained after 108 days is 1.5625%
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why would methyl salicylate be much more volatile than salicylic acid? refer to the structures of the acid and ester to explain your reasoning.
The reason that methyl salicylate be much more volatile than salicylic acid is because:
Methyl salicylate (MeSA) is a volatile that has been demonstrated to help plants defend themselves from diseases and some herbivores, most notably aphids. It has been demonstrated to have the ability to manage the aphid pest, but little is known about its mode of action, particularly the induced plant-mediated effects.Salicylic acid is it flammable?Salicylic acid's COOH group is esterified with methanol in methyl salicylate (oil of wintergreen), whereas acetylsalicylic acid (aspirin) has acetic acid as the acid component of the ester and salicylic acid provides the phenolic OH group.
Note that Methyl salicylate, a volatile methyl ester of salicylic acid, can also diffuse into the atmosphere and aid in plant-plant communication.
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What is the product of the combustion reaction of lithium?
The product of the combustion reaction of lithium is = Lithium Oxide
Lithium-like elements such as sodium and potassium are always stored in air-tight storage to avoid exposure to the air because they start a reaction with the gases present in the atmosphere to avoid this these elements are stored in oil (Lithium in fact float on the oil but the reaction is prevented).
When the process of combustion of lithium starts, a strong red-tinted flame is observed because of its burning.
The following equation shows what happens during the combustion of Lithium in the presence of Oxygen-
4Li + [tex]O_{2}[/tex] → 2[tex]Li_{2}[/tex]O
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Suppose you found a material in which 12. 5% of the original radioactive atoms were present. If the half-life is 47 years, how old is the material?
The response dates back 141 years. The formula (1/2)n = x can be used to compute it. x is the remaining fraction, There are n half-lives in total.
How do you determine a radioactive substance's half-life?The amount of time needed for the reactant concentration to drop to half its initial value is known as the half-life of a reaction. A first-order reaction's half-life is a constant that is correlated with its rate constant radioactive atoms: t1/2 = 0.693/k.
How many half life does it take for a radioactive substance, such as a 1 C 3 b2 D 4, to decay to 12.5 percent of its initial volume?The period of time it takes for half of the atoms in a given sample to experience radioactive, or nuclear, decay, is known as the half-life of a radioisotope.
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What are some of the disadvantages of electron microscopy?
Explain
A type of microscope known as an electron microscope uses an accelerated electron beam as its illuminating source.
The electron microscope offers benefits and drawbacks. One of the biggest drawbacks of the electron microscope, though, is that it cannot examine live samples. As a result of utilizing this microscope to view microorganisms, the following drawbacks are listed:
*Samples must be exposed to analysis in a vacuum state since other molecules in the air easily scatter electrons. This states that using this microscope to study live specimens is not possible.
*Additionally, the requirement that the sample be evaluated in a vacuum state makes it impossible to comprehend biological interactions in various bacteria.
*When investigating microorganisms, an electron microscope can only provide black-and-white images, which is not ideal.
* Equipment as expensive and specialised as electron microscopes. The employment of an electron microscope in the research could be counterproductive because most studies have little funding.
* For proper use of this technology, specialized operators, who may need years of training, are needed to operate electron microscopes.
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