Question 1

What is the molarity of an NaI solution that contains 4.5 g of NaI in 21.0 mL of solution?

Accepted Answer

To find the molarity, first convert grams of NaI to moles. The molar mass of NaI (sodium iodide) is approximately 149.89 g/mol. So, $4.5 \, \text{g NaI} \times \frac{1 \, \text{mol}}{149.89 \, \text{g}} = 0.030 \, \text{mol NaI}$. Then, convert the volume from mL to L: $21.0 \, \text{mL} = 0.021 \, \text{L}$. Finally, molarity $M = \frac{\text{moles of solute}}{\text{liters of solution}} = \frac{0.030 \, \text{mol}}{0.021 \, \text{L}} \approx 1.4 \, \text{M}$.

Question 2

What is the pH of 4.1 × 10−³ M HCl(aq)?

Accepted Answer

The answer of What is the pH of 4.1 ×...

Question 3

A 1.078 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 2.451 g CO₂ and 1.003 g H₂O.What mass of oxygen is contained in the original sample?

Accepted Answer

The mass of oxygen in the original sample can be found by subtracting the masses of carbon and hydrogen (found in the CO2 and H2O produced) from the total mass of the sample. The mass of carbon in CO2 is found by the ratio of the molar masses (12/44) times the mass of CO2 produced, and the mass of hydrogen in H2O is found by the ratio of the molar masses (2/18) times the mass of H2O produced. Subtracting these from the total sample mass gives the mass of oxygen in the sample.

Question 4

A mass of 0.4113 g of an unknown acid,HA,is titrated with sodium hydroxide,NaOH.If the acid reacts with 28.10 mL of 0.1055 M aqueous sodium hydroxide,what is the molar mass of the acid?

Accepted Answer

First, calculate the moles of NaOH used: $28.10 \, \text{mL} \times \frac{0.1055 \, \text{mol}}{1000 \, \text{mL}} = 0.002965 \, \text{mol}$. Since the reaction between HA and NaOH is 1:1, the moles of HA are also 0.002965. The molar mass of HA is then calculated by dividing the mass of the acid by the moles of acid: $\frac{0.4113 \, \text{g}}{0.002965 \, \text{mol}} = 138.7 \, \text{g/mol}$.

Question 5

The combustion of 0.0272 mole of a hydrocarbon produces 1.9609 g H₂O and 3.5927 g CO₂.What is the molar mass of the hydrocarbon?

Accepted Answer

First, we need to balance the chemical equation for the combustion of the hydrocarbon:
CnHm + (n + m/4)O2 → nCO2 + m/2 H2O
From the given information, we can see that:
nCO2 = 3.5927 g CO2 = 0.1001 mol CO2 (using molar mass of CO2 = 44.01 g/mol)
m/2 H2O = 1.9609 g H2O = 0.1092 mol H2O (using molar mass of H2O = 18.02 g/mol)
Since the mole ratio of CO2 to hydrocarbon (CnHm) in the balanced equation is 1:1, we have:
0.1001 mol CO2 = 0.0272 mol CnHm
Therefore, the molar mass of the hydrocarbon is:
molar mass of hydrocarbon = (mass of hydrocarbon/moles of hydrocarbon) = (1.9609 g + 3.5927 g)/0.0272 mol = 193.78 g/mol
However, this is not the molar mass of the hydrocarbon itself, as it includes the mass of the oxygen in both CO2 and H2O. To obtain the molar mass of the hydrocarbon, we need to subtract the mass of the oxygen atoms from the total molar mass. 
molar mass of C = 12.01 g/mol
molar mass of H = 1.01 g/mol
molar mass of O = 16.00 g/mol
From the balanced equation, we know that for every mole of CO2 produced, there are n moles of O2 consumed, where n is the coefficient of O2 in the balanced equation. Similarly, for every mole of H2O produced, there are m/2 moles of O2 consumed. Thus:
moles of O2 consumed = n*(0.0272 mol CO2) + (m/2)*(0.0272 mol H2O)
moles of O2 consumed = n*(0.0272 mol) + (m/2)*(0.1092 mol)
moles of O2 consumed = 0.0272n + 0.0546m
From the balanced equation, we also know that the total number of moles of C and H is n + m. Thus:
mass of C in hydrocarbon = 0.0272n*(12.01 g/mol)
mass of H in hydrocarbon = 0.0272m*(1.01 g/mol)
molar mass of hydrocarbon = (mass of C + mass of H + mass of O)/0.0272 mol
molar mass of hydrocarbon = [0.0272n*(12.01 g/mol) + 0.0272m*(1.01 g/mol) + mole of O2 consumed*(16.00 g/mol)]/0.0272 mol
Substituting the expression for moles of O2 consumed into the equation above, we get:
molar mass of hydrocarbon = [0.0272n*(12.01 g/mol) + 0.0272m*(1.01 g/mol) + (0.0272n + 0.0546m)*(16.00 g/mol)]/0.0272 mol
Simplifying, we get:
molar mass of hydrocarbon = (12.01n + 1.01m + 2.1732n + 1.7656m)/0.0272
molar mass of hydrocarbon = 464.18n + 65.99m
Now we have two equations:
- 0.1001 mol CO2 = 0.0272 mol CnHm
- molar mass of hydrocarbon = 464.18n + 65.99m
We can use these equations to solve for n and m. Multiplying the first equation by the coefficients in the balanced equation (n and m/4), we get:
n*0.1001 mol CO2 = n*0.0272 mol CnHm
0.025025n mol O2 = m/4*0.0272 mol CnHm
0.92345n = 0.0272m
From the equation for the molar mass of the hydrocarbon, we can substitute 0.92345n for 0.0272m:
molar mass of hydrocarbon = 464.18n + 60.589n = 524.769n
Substituting 0.92345n for m, we get:
molar mass of hydrocarbon = 464.18n + 60.589n = 524.769n
Substituting n = 0.0272mol/0.1001mol and solving for the molar mass of the hydrocarbon, we get:
molar mass of hydrocarbon = 44.068 g/mol, which is closest to choice C (44.1 g/mol)

Question 6

A dilute solution is prepared by transferring 35.00 mL of a 0.6363 M stock solution to a 900.0 mL volumetric flask and diluting to mark.What is the molarity of this dilute solution?

Accepted Answer

The molarity of the dilute solution can be calculated using the dilution formula $M_1V_1 = M_2V_2$, where $M_1$ and $V_1$ are the molarity and volume of the initial solution, and $M_2$ and $V_2$ are the molarity and volume of the final solution. Substituting the given values, $0.6363 \, \text{M} \times 35.00 \, \text{mL} = M_2 \times 900.0 \, \text{mL}$. Solving for $M_2$ gives $M_2 = \frac{0.6363 \, \text{M} \times 35.00 \, \text{mL}}{900.0 \, \text{mL}} = 0.02474 \, \text{M}$.

Question 7

Zn reacts with hydrochloric acid. Zn(s)+ 2 HCl(aq)→ ZnCl₂(aq)+ H₂(g) What volume of 3.05 M HCl(aq)will react with 25.0 g Zn(s)?

Accepted Answer

First, calculate the moles of Zn: $ \frac{25.0 \, \text{g Zn}}{65.38 \, \text{g/mol}} = 0.382 \, \text{mol Zn} $. According to the balanced equation, 1 mole of Zn reacts with 2 moles of HCl. Therefore, $0.382 \, \text{mol Zn} \times 2 = 0.764 \, \text{mol HCl}$ is needed. To find the volume of 3.05 M HCl required: $ \frac{0.764 \, \text{mol HCl}}{3.05 \, \text{mol/L}} = 0.251 \, \text{L} $.

Question 8

In order to dilute 77.1 mL of 0.778 M HCl to 0.100 M,the volume of water that must be added is

Accepted Answer

The answer of In order to dilute 77.1 mL of...

Question 9

How many moles of sulfate ions are there in a 0.650-L solution of 0.312 M Al₂(SO₄)₃?

Accepted Answer

The formula Al(SO4)3 indicates that there are three sulfate ions per one aluminum ion. 
To find the number of moles of sulfate ions present in the solution, we need to calculate the total moles of Al(SO4)3 present in the solution and then multiply it by the number of sulfate ions per one Al(SO4)3 molecule.

moles Al(SO4)3 = volume of solution (L) x molarity of solution

moles Al(SO4)3 = 0.650 L x 0.312 mol/L

moles Al(SO4)3 = 0.203 mol

To find the number of moles of sulfate ions, we need to multiply the moles of Al(SO4)3 by the number of sulfate ions per one Al(SO4)3 molecule.

moles of sulfate ions = moles of Al(SO4)3 x 3

moles of sulfate ions = 0.203 mol x 3

moles of sulfate ions = 0.608 mol

Therefore, the answer is B) 0.608 mol.

Question 10

The pH of an aqueous sodium hydroxide solution is 12.83.What is the hydronium ion concentration of this solution?

Accepted Answer

The hydronium ion concentration in a solution is given by $ [H_3O^+] = 10^{-pH} $. For a solution with a pH of 12.83, $ [H_3O^+] = 10^{-12.83} = 1.5 \times 10^{-13} $ M.

Question 11

A 2.197 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 4.197 g CO₂ and 2.578 g H₂O.What is the empirical formula of the compound?

Accepted Answer

The answer of A 2.197 g sample of a compound...

Question 12

Naphthalene,a hydrocarbon,has an approximate molar mass of 128 g/mole.If the combustion of 0.6400 g of naphthalene produces 0.3599 g of H₂O and 2.1977 g of CO₂,what is the molecular formula of this compound?

Accepted Answer

Naphthalene's molecular formula is C10H8. This is determined by analyzing the combustion products (CO2 and H2O) and using the molar mass. The given data leads to the calculation of carbon and hydrogen amounts, aligning with the formula C10H8.

Question 13

What volume of 1.27 M HCl is required to prepare 197.4 mL of 0.456 M HCl?

Accepted Answer

To find the volume of the original solution needed, use the dilution formula $M_1V_1 = M_2V_2$, where $M_1$ and $V_1$ are the molarity and volume of the initial solution, and $M_2$ and $V_2$ are the molarity and volume of the final solution. Plugging in the given values: $1.27 \times V_1 = 0.456 \times 197.4$. Solving for $V_1$ gives approximately 70.9 mL.

Question 14

Soft drink bottles are made of polyethylene terephthalate (PET),a polymer composed of carbon,hydrogen,and oxygen.If 1.9022 g PET is burned in oxygen it produces 0.6585 g H₂O and 4.0216 g CO₂.What is the empirical formula of PET?

Accepted Answer

The answer of Soft drink bottles are made of polyethylene...

Question 15

The pH of a vinegar solution is 4.15.What is the H₃O⁺ concentration of the solution?

Accepted Answer

The pH of a solution is calculated using the formula pH = -log[H+], where [H+] is the concentration of hydrogen ions in moles per liter (M). Given a pH of 4.15, the concentration of hydrogen ions can be calculated as [H+] = 10^-4.15 = 7.1 × 10^-5 M.

Question 16

An aqueous nitric acid solution has a pH of 2.15.What mass of nitric acid,HNO₃,is present in 20.0 L of this solution?

Accepted Answer

The pH of 2.15 corresponds to a hydrogen ion concentration of 10^(-2.15) M. For nitric acid, which is a strong acid, this is also the concentration of HNO3. Calculate the moles of HNO3 in 20.0 L and then convert to grams using the molar mass of HNO3 (63.01 g/mol).

Question 17

What mass of Na₂CO₃ is present in 0.700 L of a 0.396 M Na₂CO₃ solution?

Accepted Answer

To find the mass of Na2CO3 in the solution, use the formula: mass = molarity × volume × molar mass. The molar mass of Na2CO3 is approximately 106 g/mol. So, mass = 0.396 mol/L × 0.700 L × 106 g/mol = 29.4 g.

Question 18

What minimum mass of cobalt (II)nitrate must be added to 60.0 mL of a 0.0999 M phosphate solution in order to completely precipitate all of the phosphate as solid cobalt (II)phosphate? 2PO₄^3-(aq)+ 3Co(NO₃)₂(aq)→ Co₃(PO₄)₂(s)+ 6NO₃^-(aq)

Accepted Answer

The balanced chemical equation for the reaction is:$$ \text{2 PO}_4^{3-} (aq) + 3 \text{Co(NO}_3)_2 (aq) \rightarrow \text{Co}_3(PO_4)_2 (s) + 6 \text{NO}_3^- (aq) $$From the equation, 3 moles of cobalt(II) nitrate are needed to precipitate 2 moles of phosphate ions. First, calculate the moles of phosphate in the solution:$$ \text{Moles of phosphate} = 0.0999 \, \text{M} \times 0.0600 \, \text{L} = 0.005994 \, \text{mol} $$According to the stoichiometry of the reaction, the moles of cobalt(II) nitrate needed are:$$ \text{Moles of Co(NO}_3)_2 = \frac{3}{2} \times 0.005994 \, \text{mol} = 0.008991 \, \text{mol} $$The molar mass of cobalt(II) nitrate, Co(NO3)2, is approximately 182.94 g/mol (Co = 58.93, N = 14.01, O = 16.00). Therefore, the mass of cobalt(II) nitrate required is:$$ \text{Mass} = 0.008991 \, \text{mol} \times 182.94 \, \text{g/mol} = 1.645 \, \text{g} $$Thus, the minimum mass of cobalt(II) nitrate required is approximately 1.64 g.

Question 19

Polyethylene is a polymer consisting of only carbon and hydrogen.If 2.300 g of the polymer is burned in oxygen it produces 2.955 g of H₂O and 7.217 g of CO₂.Determine the empirical formula of polyethylene.

Accepted Answer

To determine the empirical formula, we need to find the ratio of carbon and hydrogen atoms in the polymer. First, we need to calculate the amount of carbon and hydrogen in the polymer. We know that the only products of the combustion are H₂O and CO₂, which means that all the carbon and hydrogen in the polymer have been converted into these two compounds. From H₂O, we can see that there is 1 carbon atom and 2 hydrogen atoms for every oxygen atom. Therefore, the amount of carbon and hydrogen from the polymer that contribute to H₂O are: Carbon = 2.955 g / (32.06 g/mol) = 0.092 moles Hydrogen = 2 x 0.092 moles = 0.184 moles Similarly, from CO₂, we can see that there is 1 carbon atom and 1 oxygen atom for every sulfur atom. Therefore, the amount of carbon and hydrogen from the polymer that contribute to CO₂ are: Carbon = 7.217 g / (44.01 g/mol) = 0.164 moles Oxygen = 7.217 g / (32.06 g/mol) = 0.225 moles Now we can calculate the ratio of carbon to hydrogen: Carbon/Hydrogen = (0.092 moles / 0.184 moles) = 0.5 This means that there are equal number of carbon and hydrogen atoms in the polymer. The only choice that represents this ratio of atoms is B: CH₂.

Question 20

What volume of 0.742 M Na₂CO₃ solution contains 44.9 g of Na₂CO₃?

Accepted Answer

First, we need to use the molar mass of Na₂CO₃ to convert the given mass of 44.9 g to moles: 44.9 g Na₂CO₃ × (1 mol Na₂CO₃/126.04 g Na₂CO₃) = 0.356 mol Na₂CO₃ Then, we can use the given concentration of the solution to calculate the volume of solution needed to contain 0.356 mol of Na₂CO₃: 0.742 mol Na₂CO₃/L × V = 0.356 mol Na₂CO₃ V = 0.356 mol Na₂CO₃ / 0.742 mol Na₂CO₃/L = 0.479 L = 0.571 L (rounded to 3 significant figures) Therefore, the answer is C, 0.571 L.

Quiz 5: Stoichiometry: Quantitative Information About Chemical Reactions

What is the molarity of an NaI solution that contains 4.5 g of NaI in 21.0 mL of solution?

What is the pH of 4.1 × 10−³ M HCl(aq) ?

A 1.078 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 2.451 g CO₂ and 1.003 g H₂O.What mass of oxygen is contained in the original sample?

A mass of 0.4113 g of an unknown acid,HA,is titrated with sodium hydroxide,NaOH.If the acid reacts with 28.10 mL of 0.1055 M aqueous sodium hydroxide,what is the molar mass of the acid?

The combustion of 0.0272 mole of a hydrocarbon produces 1.9609 g H₂O and 3.5927 g CO₂.What is the molar mass of the hydrocarbon?

A dilute solution is prepared by transferring 35.00 mL of a 0.6363 M stock solution to a 900.0 mL volumetric flask and diluting to mark.What is the molarity of this dilute solution?

Zn reacts with hydrochloric acid. Zn(s) + 2 HCl(aq) → ZnCl₂(aq) + H₂(g) What volume of 3.05 M HCl(aq) will react with 25.0 g Zn(s) ?

In order to dilute 77.1 mL of 0.778 M HCl to 0.100 M,the volume of water that must be added is

How many moles of sulfate ions are there in a 0.650-L solution of 0.312 M Al₂(SO₄) ₃?

The pH of an aqueous sodium hydroxide solution is 12.83.What is the hydronium ion concentration of this solution?

A 2.197 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 4.197 g CO₂ and 2.578 g H₂O.What is the empirical formula of the compound?

Naphthalene,a hydrocarbon,has an approximate molar mass of 128 g/mole.If the combustion of 0.6400 g of naphthalene produces 0.3599 g of H₂O and 2.1977 g of CO₂,what is the molecular formula of this compound?

What volume of 1.27 M HCl is required to prepare 197.4 mL of 0.456 M HCl?

Soft drink bottles are made of polyethylene terephthalate (PET) ,a polymer composed of carbon,hydrogen,and oxygen.If 1.9022 g PET is burned in oxygen it produces 0.6585 g H₂O and 4.0216 g CO₂.What is the empirical formula of PET?

The pH of a vinegar solution is 4.15.What is the H₃O⁺ concentration of the solution?

An aqueous nitric acid solution has a pH of 2.15.What mass of nitric acid,HNO₃,is present in 20.0 L of this solution?

What mass of Na₂CO₃ is present in 0.700 L of a 0.396 M Na₂CO₃ solution?

What minimum mass of cobalt (II) nitrate must be added to 60.0 mL of a 0.0999 M phosphate solution in order to completely precipitate all of the phosphate as solid cobalt (II) phosphate? 2PO₄^3-(aq) + 3Co(NO₃) ₂(aq) → Co₃(PO₄) ₂(s) + 6NO₃^-(aq)

Polyethylene is a polymer consisting of only carbon and hydrogen.If 2.300 g of the polymer is burned in oxygen it produces 2.955 g of H₂O and 7.217 g of CO₂.Determine the empirical formula of polyethylene.

What volume of 0.742 M Na₂CO₃ solution contains 44.9 g of Na₂CO₃?

Quiz 5: Stoichiometry: Quantitative Information About Chemical Reactions

What is the molarity of an NaI solution that contains 4.5 g of NaI in 21.0 mL of solution?

What is the pH of 4.1 × 10−3 M HCl(aq) ?

A 1.078 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 2.451 g CO2 and 1.003 g H2O.What mass of oxygen is contained in the original sample?

A mass of 0.4113 g of an unknown acid,HA,is titrated with sodium hydroxide,NaOH.If the acid reacts with 28.10 mL of 0.1055 M aqueous sodium hydroxide,what is the molar mass of the acid?

The combustion of 0.0272 mole of a hydrocarbon produces 1.9609 g H2O and 3.5927 g CO2.What is the molar mass of the hydrocarbon?

A dilute solution is prepared by transferring 35.00 mL of a 0.6363 M stock solution to a 900.0 mL volumetric flask and diluting to mark.What is the molarity of this dilute solution?

Zn reacts with hydrochloric acid. Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) What volume of 3.05 M HCl(aq) will react with 25.0 g Zn(s) ?

In order to dilute 77.1 mL of 0.778 M HCl to 0.100 M,the volume of water that must be added is

How many moles of sulfate ions are there in a 0.650-L solution of 0.312 M Al2(SO4) 3?

The pH of an aqueous sodium hydroxide solution is 12.83.What is the hydronium ion concentration of this solution?

A 2.197 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 4.197 g CO2 and 2.578 g H2O.What is the empirical formula of the compound?

Naphthalene,a hydrocarbon,has an approximate molar mass of 128 g/mole.If the combustion of 0.6400 g of naphthalene produces 0.3599 g of H2O and 2.1977 g of CO2,what is the molecular formula of this compound?

What volume of 1.27 M HCl is required to prepare 197.4 mL of 0.456 M HCl?

Soft drink bottles are made of polyethylene terephthalate (PET) ,a polymer composed of carbon,hydrogen,and oxygen.If 1.9022 g PET is burned in oxygen it produces 0.6585 g H2O and 4.0216 g CO2.What is the empirical formula of PET?

The pH of a vinegar solution is 4.15.What is the H3O+ concentration of the solution?

An aqueous nitric acid solution has a pH of 2.15.What mass of nitric acid,HNO3,is present in 20.0 L of this solution?

What mass of Na2CO3 is present in 0.700 L of a 0.396 M Na2CO3 solution?

What minimum mass of cobalt (II) nitrate must be added to 60.0 mL of a 0.0999 M phosphate solution in order to completely precipitate all of the phosphate as solid cobalt (II) phosphate? 2PO43-(aq) + 3Co(NO3) 2(aq) → Co3(PO4) 2(s) + 6NO3-(aq)

Polyethylene is a polymer consisting of only carbon and hydrogen.If 2.300 g of the polymer is burned in oxygen it produces 2.955 g of H2O and 7.217 g of CO2.Determine the empirical formula of polyethylene.

What volume of 0.742 M Na2CO3 solution contains 44.9 g of Na2CO3?

What is the pH of 4.1 × 10−³ M HCl(aq) ?

A 1.078 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 2.451 g CO₂ and 1.003 g H₂O.What mass of oxygen is contained in the original sample?

The combustion of 0.0272 mole of a hydrocarbon produces 1.9609 g H₂O and 3.5927 g CO₂.What is the molar mass of the hydrocarbon?

Zn reacts with hydrochloric acid. Zn(s) + 2 HCl(aq) → ZnCl₂(aq) + H₂(g) What volume of 3.05 M HCl(aq) will react with 25.0 g Zn(s) ?

How many moles of sulfate ions are there in a 0.650-L solution of 0.312 M Al₂(SO₄) ₃?

A 2.197 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 4.197 g CO₂ and 2.578 g H₂O.What is the empirical formula of the compound?

Naphthalene,a hydrocarbon,has an approximate molar mass of 128 g/mole.If the combustion of 0.6400 g of naphthalene produces 0.3599 g of H₂O and 2.1977 g of CO₂,what is the molecular formula of this compound?

Soft drink bottles are made of polyethylene terephthalate (PET) ,a polymer composed of carbon,hydrogen,and oxygen.If 1.9022 g PET is burned in oxygen it produces 0.6585 g H₂O and 4.0216 g CO₂.What is the empirical formula of PET?

The pH of a vinegar solution is 4.15.What is the H₃O⁺ concentration of the solution?

An aqueous nitric acid solution has a pH of 2.15.What mass of nitric acid,HNO₃,is present in 20.0 L of this solution?

What mass of Na₂CO₃ is present in 0.700 L of a 0.396 M Na₂CO₃ solution?

What minimum mass of cobalt (II) nitrate must be added to 60.0 mL of a 0.0999 M phosphate solution in order to completely precipitate all of the phosphate as solid cobalt (II) phosphate? 2PO₄^3-(aq) + 3Co(NO₃) ₂(aq) → Co₃(PO₄) ₂(s) + 6NO₃^-(aq)

Polyethylene is a polymer consisting of only carbon and hydrogen.If 2.300 g of the polymer is burned in oxygen it produces 2.955 g of H₂O and 7.217 g of CO₂.Determine the empirical formula of polyethylene.

What volume of 0.742 M Na₂CO₃ solution contains 44.9 g of Na₂CO₃?