8. In the lab, you are asked to prepare 150 mL of an 85 g/L solution and then use the original
solution to make 500 mL of a 50 g/L solution.
a) How much solute is needed to prepare the original solution? (Think: C = M/V)
b) How much of the original solution (mL) is needed to make the diluted solution?
For the original solution,
Concentration = 85g/L = 85g/1000ml
Required Volume = 150ml
(a)
Concentration = Mass/Volume
⇒ 85g/1000ml = Mass of the solute/150ml
⇒ Mass of the solute = 85 x 150/1000
⇒ Mass of the solute = 12.75 grams
Hence, 12.75 grams of the solute is required to prepare the original solution.
(b)
Now,
Concentration of the original solution = 85g/L = M1
Required concentration = 50g/L = M2
Final Volume = 500 ml = V2
Required Volume from the original solution = V1 =?
As we know,
M1V1 = M2V2
Hence,
85g/L x V1 = 500 ml x 50g/L
⇒ V1 = 500 X 50 / 85
⇒ V1 = 294.11 ml
Therefore, 294.11 ml of the original solution is required to make the diluted solution.
What is a Stock solution?A stock solution is a very potent mixture. These solutions are quite helpful since we may take a small amount of the stock solution and dilute it to the required concentration. These ready-to-use chemical reagents can be prepared quickly thanks to these stock solutions. It also aids in material conservation. As a result, just the amount of stock and solvent required for the dilution process is consumed when utilizing a stock solution to low-concentrated solution. Because we simply need to dilute the stock solution instead of preparing the solution using many reagents and complex procedures, it is also crucial to conserve storage space. Additionally, it enhances experiment accuracy.A chemical reagent is present in vast quantities as a stock solution. It has a uniform concentration. Examples of typical stock solutions in laboratories are sodium hydroxide and hydrochloric acid. These play a critical role in creating titration-related solution preparations.To learn more about the Stock solution, refer to:
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an aqueous solution containing 9.63 g of an optically-pure compound was diluted to 2.00×102 ml with water and placed in a 20.0 cm long polarimeter tube. the measured rotation was −2.67° at 25° c. calculate the specific rotation of the compound.
Based on the optical rotation equation, the specific rotation of the compound is -27.73 °C*mL/g*dm,
The optical rotation equation looks like this:
α = [α] * c * l
α - measured optical rotation (-2.67°)
[α] - specific rotation of the compound, temperature, and wavelength used, usually in °C, although more accurately in °C*mL/g*dm
c - concentration of the compound in g/mL (9.63 g / 200 mL = 0.04815 g/mL)
l - length of the polarimeter cell in dm (20.0 cm = 2.00 dm)
If we transform the equation we get:
[α] = α / (c * l) = -2.67° / (0.04815 g/mL * 2.00 dm) = -27.73 °C*mL/g*dm
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Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation _____ carbons are fully oxidized to _____, while _____ carbons remain in _____.
Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation two carbons are fully oxidized to CO₂, while four carbons remain in acetyl groups.
Pyruvate is a compound containing 3 carbon molecules formed from the first stage of glycolysis. One glucose molecule is reduced to two pyruvate molecules in the cytosol of the cell. The pyruvate then enters the matrix of the mitochondria, where pyruvate oxidation takes place.
Pyruvate oxidation is the reaction that connects glycolysis to the citric acid cycle or the Kreb's cycle. In eukaryotic cells, it occurs in the matrix of the mitochondria, but in prokaryotic cells, it occurs in the cytoplasm.
First, a carboxyl group is removed from the pyruvate. This carboxyl group is reduced to carbon dioxide (CO₂). The two-carbon molecule from the pyruvate called an acetyl is then attached to an organic compound called Coenzyme A (CoA), forming acetyl-CoA. This acetyl-CoA is the end product of pyruvate oxidation and acts as fuel for the next stage of cellular respiration, the citric acid cycle.
Thus, at the end of pyruvate oxidation, two carbon atoms of the 6 carbons in the starting glucose molecule are oxidized to two molecules of CO₂, while the remaining four carbons are in acetyl-CoA.
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Given 6.00 moles of oxygen gas, O2 (g), how many liters will this sample occupy at STP?
A. 269 L
B. 67.2 L
C. 134 L
D. 22.4 L
Answer:
Explanation:
The only option that would have 6 moles is 67.2 L
It is an active ingredient in some oral anesthetics used in sore throat sprays. What is the molar mass of phenol? please answer in g/mol to the nearest whole number.
Phenol has a molar mass of 94.11 g/mol.It is an active ingredient in many oral anesthetics that is used in sore throat sprays.
To calculate molar mass the following steps must be followed:
1) Divide the molar mass of phenol by the molar mass of carbon. This will give you the number of moles of carbon in phenol.
2) Add the number of moles of carbon to the number of moles of hydrogen. This will give you the total number of moles in phenol.
3) Multiply the total number of moles by the molar mass of carbon.
This will give you the molar mass of phenol.
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Explain why melting ice is an example of an endothermic reaction.
Melting ice is an example of an endothermic reaction because it absorbs heat.
When ice melt it convert into water , the phase transition from solid to liquid. In solid phase the particles are held together with strong force of attraction. when it changes to liquid , the intermolecular attraction between particles will become weak and this is due to energy is absorbed by the system. The changes takes place only when the ice absorbed heat from its surrounding. when the heat is absorbed during the reaction it is called as Endothermic reaction. while when heat is release during the reaction it is called as exothermic reaction.
Thus, The Melting ice is an example of an endothermic reaction because it absorbs heat.
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what is the identity of the element that produced the unknown emission spectrum and what information does the spectrum give about the source of the element?
Each atom has a wide range of potential electron transitions. There is a distinct energy differential for each transition. An emission spectrum is made up of these transitions. Similar to how fingerprints are unique to individuals, these emission spectra are to each element.
What is emission spectrum?
The electromagnetic radiation spectrum produced when an electron changes from a high energy state to a lower energy state is known as the emission spectrum of a chemical element or chemical compound. The energy difference between the two states is equal to the photon energy of the emitted photon.
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calculate (a) the (molar) gibbs energy of mixing, (b) the (molar) entropy of mixing when the two major components of air (nitrogen and oxygen) are mixed to form air at 298 k. the mole fractions of n2 and o2 are 0.78 and 0.22, respectively. is the mixing spontaneous?
The entropy of mixing of nitrogen and oxygen gases of mole fractions of 0.78 and 0.22 respectively is -4.34 J and the molar Gibbs energy of mixing is - 1295.7 J. Negative sign of Gibbs energy indicates that the reaction is spontaneous.
What is spontaneous reaction?A spontaneous reaction is the one which occurs naturally without any urge or external factor or force. Spontaneity of a reaction can be determined from the Gibbs energy of the reaction. If Gibbs energy is negative then, the reaction is spontaneous and if positive reaction will be non- spontaneous.
Entropy of mixing is calculated using the mole fractions of the two gases Xa and Xb as written as follows:
ΔSmix = R (Xa in Xa + Xb in Xb).
Where R is the universal gas constant equal to 8.314 J/(K mol)
We have the mole fraction of nitrogen and oxygen in the reaction. Apply these values to the equation as follows:
ΔSmix = 8.314 (0.78 ln 0.78 + 0.22 ln 0.22)
= -4.34 J
Molar gibbs energy of mixing = RT (Xa in Xa + Xb in Xb).
Thus ΔGmix = TΔSmix
= 298 K × -4.34 J
= -1295.7 J.
Therefore, the reaction of mixing of nitrogen and oxygen is spontaneous.
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how many total atoms are in paradichlorobenzene
Answer:12
Explanation:
The chemical formula is C₆H₄Cl₂, where the Chlorines are bonded to opposite sides of the benzene ring (because of steric strain) and each of the double bonded Carbons have a Hydrogen attached to them.
You will be preparing dilutions of the stock solution and measure their absorbances. According to beer’s law, predict how the absorbance of the stock solution will compare to the measured absorbances for the diluted solution.
Answer: As a solution is diluted, the absorbance of the solution is decreased
Explanation: As a solution is diluted, the absorbance of the solution is decreased. The concept of dilution relates molar concentration and volume.M1V1=M2V2. If a 1.0 liter of a 1.0 molar solution is diluted to 2.0 molar solution, the new molar concentration is 0.50. The new concentration has been reduced by one half as the volume was doubled.Beer's law relates the concept of concentration and absorbance. According to this law, absorbance and concentration are directly proportional. If you increase the original concentration, the absorbance increases and if you dilute the solution(which means you decrease the original concentration), the absorbance will decrease in direct proportion. ;)
According to the Beer's law the absorbance of solution is directly proportional to concentration,hence on dilution the concentration decreases which decreases absorbance on a whole.
What is Beer's law?The Beer's law states that the absorbance is directly proportional to the concentration of a solution that is,A∝C .Most substances follow Beer's law from low to moderate temperature ranges only.It is not followed well in case of saturation effects which are present in highly concentrated samples.
Due to the direct relation between absorbance and concentration , absorbance is preferred over transmittance for recording the spectra.
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What is the equation for kinetic energy?
KE=1/2 mV^2
m=mass
V=velocity
What species is represented by the following information?
p+=12 n°=14 e- =10 , The species that is represented here is ;
Mg2+.
What is Mg2+?Mg has the atomic number 12 assigned to it (magnesium). Because the number of electrons is two fewer than the number of protons, the answer is ten. As a result, the two electrons are lost by the concerned element (Mg) to give rise to the Mg2+ ion.Magnesium ions (Mg2+) are divalent cations that are required for many cellular functions. Mg2+ channels such as MgtE, a prokaryotic Mg2+ channel whose gating is regulated by intracellular Mg2+ levels, maintain Mg2+ homeostasis.Magnesium is a positive ion that is doubly charged.A magnesium atom's outer electron shell contains two electrons. When it becomes an ion, it loses both, leaving it with 12 positively charged protons and 10 negatively charged electrons. This results in a +2 positive charge.Because of the Magnesium Oxide layer, it is colorless, but burning Mg metal produces an intense white.
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the element tellurium forms a(n) with the charge fill in the blank 2. the symbol for this ion is , and the name is fill in the blank 4 ion. the number of electrons in this ion is .
The element tellurium forms an ion with the charge of +4.
The symbol for this ion is Te⁴⁺ and the name is tellurium ion.
The number of electrons in this ion is 48 electrons.
What are ions?Ions are substances that are formed when atoms of elements gain or lose electrons.
There are two types of ions based on the charge the ions carry:
Cations - they have a positive charge; for example, calcium ion, Ca²⁺, ammonium ion, NH₄⁺Anions - they have a negative charge; for example Chloride ion, Cl⁻, tetraoxosulfate (vi) ion, SO₄²⁻Metallic atoms form cations by losing one or more electrons.
Non-metallic atoms form negative ions by gaining one or more electrons.
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in a neutral atom, how does the number of electrons compare to the number of protons?
Answer: The no of electron and protons are equal therefore it is equal.
Answer:
The number of electrons and protons will be equal.
Explanation:
When you have a neutral atom, the protons, neutrons and electrons are all the same amounts, that's what makes it a neutral charge.
** Hope this helps!
How will this mutation most likely affect the squirrel population?
Because the trait was caused by a mutation, it will not be passed on to any offspring, resulting in the disappearance of the trait.
Because the trait was caused by a mutation, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.
If the trait is unfavorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.
If the trait is favorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.
This mutation most likely affect the squirrel population : if the trait is favorable , it will be passed on to offspring over many generations, resulting in a population of darker squirrels.
Mutation can be defined as the changes in genetic material that is a change in DNA this lead to change in gene segment. mutation includes various factors such as UV light or mistakes during DNA replication . mutation leads to genetic variation in species. Mutation which offers survival advantage are favored by natural selection.
Thus, This mutation most likely affect the squirrel population : if the trait is favorable , it will be passed on to offspring over many generations, resulting in a population of darker squirrels.
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What are some properties of plasma?
Plasmas are less dense than solids or liquids and have no set shape or volume. Plasmas are made up of atoms with some or all of their electrons stripped away and positively charged nuclei, known as ions, roaming freely.
What is plasmas?Plasmas is defined as a type of substance in which numerous electrons freely roam around the nuclei of the atoms.
Plasma has been referred to as the fourth state of matter, alongside solid, liquid, and gas.
When one or more electrons are ripped from an atom, they form a plasma.
Thus, plasmas are less dense than solids or liquids and have no set shape or volume. Plasmas are made up of atoms with some or all of their electrons stripped away and positively charged nuclei, known as ions, roaming freely.
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Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation _____ carbons are fully oxidized to _____, while _____ carbons remain in _____.
Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation, two carbons are fully oxidized to CO2, while four carbons remain in acetyl groups.
This is further explained below.
What are acetyl groups.?Generally, The acetyl group is a functional group that is used in organic chemistry.
Its chemical formula is [tex]COCH_3,[/tex] and its structural formula is [tex]CCH_3.[/tex]Occasionally, the sign Ac will be used to symbolize it.
In the nomenclature used by the IUPAC, acetyl is referred to as ethanol, despite the fact that very few people actually use this name. A methyl group is found inside the acetyl group, and it is single-bonded to a carbonyl.
In conclusion, At the end of the pyruvate oxidation process, two of the six carbons that were present in the glucose molecule at the beginning are converted into carbon dioxide, while the other four carbons are still present as acetyl groups.
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How does adding deionized water into a solution containing ions affect the electrical conductivity of the solution?.
Adding deionized water into a solution containing ions will affect the electrical conductivity of the solution because the ions in the solution will be attracted to the water molecules.
Deionized water is water that has had its ions removed. This means that it will not conduct electricity.It will cause the ions to be more spread out in the solution, which will decrease the electrical conductivity of the solution. When deionized water is added to a solution containing ions, the electrical conductivity of the solution will be reduced. The reason for this is that the ions in the solution will be attracted to the water molecules, and this will reduce the number of ions that are available to conduct electricity.
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Given: 0.156M C2H4O260mL H2O4.17 pKaIn a NaOH and C2H4O2 titration
ANSWER
STEP-BY-STEP EXPLANATION
Which of the elements shown below would you predict to be the most reactive? Justify your answer.
Answer:
Lithium is the most reactive out of them.
Explanation:
For this question, we will be looking at the valence electrons each one has. Valence electrons are the electrons that are on the outermost electron shell (the outer circle around each of them).
Lithium has 2 electron shells: the innermost has 2 electrons (this circle can only hold up to 2 electrons), and the outermost circle has 1 electron (this circle can hold up to 8 electrons).
Helium has only 1 electron shell and within it, it has 2 electrons (remember this is the maximum amount this circle can take).
Argon has 3 electron shells: the innermost has 2 electrons (the maximum this circle can have), the middle one has 8 electrons (the maximum this circle can have), and the outermost circle has 8 electrons around it (this circle also holds a maximum of 8 electrons).
Now let's look at the electrons present only on the outer shell of each of them (these are called valence electrons).
Lithium has only 1 electron on its outermost shell but this shell can have up to 8 electrons.
Helium has 2 electrons, the maximum amount that circle can have.
Argon has 8 electrons, the maximum that circle can have.
-Every atom has the goal of wanting to be stable, by completing the maximum amount on their outermost shell by either gaining or losing electrons.
Since Helium and Argon already have the maximum amount of electrons their outermost circle can have, they are already stable and neither want to gain or lose electrons.
Lithium is our only option that has an incomplete outermost electron shell with only 1 out of the 8 electrons it can have.
It is easier for Lithium to give away that 1 electron it has and then have a complete inner-circle after giving out that 1 electron (it would then look like Helium), than to gain 7 electrons and complete the circle.
This is why Lithium is very reactive, because it is constantly looking to find someone to give away their electron to and become stable. Lithium also has a charge of (+1), which means that it gives away one of its electrons.
In a parallel circuit with identical light bulbs, which of these is true? A A battery is not the source of voltage. B There is only one resistor, such as a light bulb. C The circuit is left open so that current cannot flow. D Adding more identical light bulbs will not change their brightness.
In a parallel circuit with identical light bulbs, the statement D is true. D Adding more identical light bulbs will not change their brightness.
A parallel circuit has two or more paths for modern to waft through. Voltage is equal across everything of the parallel circuit. The sum of the currents thru each route is equal to the entire modern that flows from the supply.
A parallel circuit has one feature: to preserve the power flowing while one pathway is interrupted. A top instance is mild furnishings that use more than one mild bulb. when an unmarried bulb within the fixture goes the light fixture maintains to operate.
In a chain circuit, the modern-day thru every one of the additives is the same, and the voltage across the circuit is the sum of the voltages throughout every issue. In a parallel circuit, the voltage across every one of the components is equal, and the total cutting edge is the sum of the currents via each element.
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How many of each element would you find in AI(NO3)3?
a. Aluminum : _________
b. Hydrogen : __________
c. Oxygen : _____________
Answer:
you will find 3 in aluminium
hydrogen should be b 3
and oxygen is 9
a commonly used biological buffer is a made from a weak acid/conjugate base pair called ""tris"". the pka for tris acid is 8.06. you have 1.00 liters of a solution where the concentration of tris acid (ha) is 0.200 m and the concentration of tris base (a-) is 0.150 m. what is the ph of the solution?
The pH of the solution is 7.94 if the concentration of the tris acid is 0.200m and the concentration of the conjugate base is 0.150m.
The pH of this buffer can be calculated using the Henderson-Hasselbalch equation according to which the pH is equal to the sum of the pKa value and the log of the concentration of conjugate base divided by the concentration of the weak acid.
This equation can be represented as;
pH = pKa + log ([conjugate base] ÷ [weak acid])
Substituting the given values into this equation to find the pH;
pH = 8.06 + log([0.150] ÷ [0.200])
pH = 8.06 + log(0.75)
pH = 8.06 + (-0.125)
pH = 7.94
Therefore the pH of this solution is calculated to be 7.94.
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An atom of Iron contains 27 neutrons. What is its mass number?
Answer:
53
Explanation:
Iron has atomic number of 26
so mass number is 26 + 27 = 53
Iron atoms contain 27 neutrons. It has a mass of 53.
What is mass number?Rutherford demonstrated that an atom's nucleus, which is made up of protons and neutrons, contains the vast bulk of the atom's mass. The total number of protons and neutrons in an atom is referred to as the mass number. The atomic number (number of protons and neutrons) and their sum can be used to compute it.Mass number = atomic number + number of neutron. All atoms of an element have the same amount of protons, although they can have different numbers of neutrons. As a result, various isotopes of the same element can have different mass values.An electron weighs practically nothing. As a result, an atom's atomic mass and mass number are practically equal.Therefore,
Mass number= no. of proton + no. of neutrons
Atomic number= no. of proton = 26
Mass number = 26+27
= 53
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Read this paragraph.
Omar is looking forward to summer. He’ll be in the Juniors group on his swim team, and he expects the tough competition will help him improve his backstroke time. He is also looking forward to a trip to the mountains with his grandparents. If he can save $75 before the trip, he wants to try the mountain zip line described as "not for the faint of heart.” Unfortunately, Omar’s earning potential is limited. At 14 years old, it’s tough to get a "real” job, and the other prospects are limited. Omar asked a few neighbors about mowing their yards, but everyone prefers to mow their own. He has considered offering babysitting services to his aunt, but the thought of watching his wild little cousins is not appealing.
Omar is facing a problem with
.
Omar is facing a problem with money.
Is earnings the same as profit?
Businesses typically use earnings and revenue to describe their financial performance over a period of time. Profit and turnover are the two most valuable numbers in a company's financial statements.
Revenue is the total money a company earns from the sale of goods and services. Income is called the top line because it is at the top of the company's income statement, which also refers to the company's gross sales. Income is the income received before expenses are deducted. Turnover is also called turnover in some companies, because turnover includes potential returns from customers.
Profit, on the other hand, reflects the bottom line of the income statement and is the profit the company earned during the period. The profit indicator is entered in the net result of the profit and loss statement. When investors and analysts talk about a company's performance, they are talking about the company's net income or earnings.
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Which of the following examples is evidence of a physical change?
A: A person inhales oxygen and exhales carbon dioxide and water.
B:Ice cream melts in a bowl.
C:A silver spoon tarnishes over time.
D:An electrical current splits water into hydrogen and oxygen.
In the given examples ice cream melts in a bowl is an example of a physical change.
A physical change occurs when a substance transforms from one state to another i.e., the change only affects its physical properties like color, volume, shape, and phase changes.
Using water as an example, if we have it at room temperature, it is a clear liquid. If we decrease the temperature below the freezing point, the water freezes and forms ice. If we increase the temperature above the boiling point, the water turns into a gas(steam). We can see that in all three forms, the water is still composed of two hydrogen atoms and one oxygen atom. Nothing is added or subtracted from it, which means the chemical composition stays the same. The transformation of water from liquid to solid or gas is an example of a physical change.
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I need help to answer this question. I don’t understand how to do this.
Answer: Gains an extra electron in 2p orbitals it's option Y (1s²,2s², 2p⁶
calculate the molar concentration of the solution formed when 8g of sodiumhydroxide is dissolved in 1dm³of water
Answer:
wow I can't believe you. your cheating I'm giving you a f on this. unless you tell me in front of the class that you cheated. I'm joking man but seriously I don't know
describe how you can use the periodic table to charge of an ion?
Explanation:
To find the ionic charge of an element you'll need to consult your Periodic Table. On the Periodic Table metals (found on the left of the table) will be positive. Non-metals (found on the right) will be negative.
does backing contains metallic and non-metallic elements? which ones are which?