Question 1

What mass of sodium hydroxide is necessary to react with a solution containing 73.00 g HCl, according to the chemical equation below? [Molar masses: NaOH, 39.99 g/mol; HCl, 36.45 g/mol] NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

Accepted Answer

The answer of What mass of sodium hydroxide is necessary...

Question 2

How many iron atoms are present in 0.552 mol of iron?

Accepted Answer

The Avogadro's number, which is the number of particles (atoms/molecules) in one mole of substance, is 6.02 × 10^23. 
Therefore, the number of iron atoms in 0.552 mol of iron is:

0.552 mol x 6.02 × 10^23 atoms/mole = 3.32 × 10^23 atoms

So, the correct answer is D.

Question 3

How is the reaction shown below best classified? Ca(s) + 2HCl(aq) → CaCl₂(g) + H₂(g)

Accepted Answer

This is a single-replacement reaction as the calcium metal is replacing hydrogen in the hydrogen chloride to form calcium chloride and hydrogen gas.

Question 4

How many moles of Au atoms are present in one ounce of pure gold? [1 oz = 28.4 g]

Accepted Answer

Firstly, we need to convert the mass of gold in ounces to grams:

1 oz = 28.4 g

Next, we need to use the molar mass of gold to convert the mass to moles:

1 mol Au = 196.967 g Au

Number of moles of Au = (28.4 g Au) / (196.967 g Au/mol) = 0.144 mol Au

Therefore, there are 0.144 moles of Au atoms present in one ounce of pure gold and the best choice is C.

Question 5

A sample of sulfur contains 1.81 × 10²⁴ atoms of sulfur.How many moles of sulfur does this represent?

Accepted Answer

To calculate the number of moles of sulfur from the given number of atoms, we need to use Avogadro's number, which is 6.022 × 1023 atoms or molecules per mole.

Number of moles = Number of atoms ÷ Avogadro's number

Number of moles = 1.81 × 10S1U1P124 ÷ 6.022 × 10²³

Number of moles ≈ 3.01

Therefore, the answer is (B) 3.01 mol.

Question 6

How is the reaction shown below best classified? 2HgO(s) → 2Hg(l) + O₂(g)

Accepted Answer

The reaction involves the breakdown of a single compound, HgO, into two simpler substances, Hg and O2, which is characteristic of a decomposition reaction.

Question 7

Diamond is a pure form of the element carbon.If a 2 carat diamond has a mass of 0.396 g, how many carbon atoms are contained in this diamond?

Accepted Answer

The molar mass of carbon is 12.01 g/mol. The mass of the diamond is 0.396 g, so the number of moles of carbon in the diamond is:

0.396 g / 12.01 g/mol = 0.033 mol

Since each mole of carbon contains Avogadro's number of atoms (6.022 x 10^23 atoms/mol), the number of carbon atoms in the diamond is:

0.033 mol * 6.022 x 10^23 atoms/mol = 1.99 x 10^22 atoms

Therefore, the best choice is D.

Question 8

Dinitrogen monoxide, or laughing gas (N₂O), is used as a dental anesthetic and as an aerosol propellant.How many molecules of N₂O are present in a 12.6 g sample of the compound?

Accepted Answer

The answer of Dinitrogen monoxide, or laughing gas (N₂O), is...

Question 9

When the equation below is balanced with the lowest possible whole number coefficients, what is the sum of the coefficients? Ca(s) + HCl(g) → CaCl₂(s) + H₂(g)

Accepted Answer

The balanced equation is Ca(s) + 2HCl(g) → CaCl2(s) + H2(g). The sum of coefficients is 1 + 2 + 1 + 2 = 6. However, since the question asks for the lowest possible whole number coefficients, we can divide all coefficients by 2 to get the balanced equation 1Ca(s) + 1HCl(g) → 1CaCl2(s) + 1H2(g), where the sum of coefficients is 1 + 1 + 1 + 2 = 5. Therefore, the answer is choice C.

Question 10

Magnesium hydroxide, Mg(OH)₂, as "Milk of Magnesia" can be used to neutralize excess stomach acid, represented by HCl(aq) according to the chemical equation below. Mg(OH)₂(s) + 2HCl(aq) → MgCl₂(aq) + 2H₂O(l) When 5.00 g of HCl are combined with an excess of Mg(OH)₂, what mass of MgCl₂ can be produced? [Molar masses: H, 1.01 g/mol; O, 16.00 g/mol; Mg, 24.31 g/mol; Cl, 35.45 g/mol]

Accepted Answer

The answer of Magnesium hydroxide, Mg(OH)₂, as "Milk of Magnesia"...

Question 11

To convert a given number of moles into the number of atoms, one would multiply by which of the following factors?

Accepted Answer

To convert moles to atoms, we need to use Avogadro's number, which is the number of atoms in one mole of a substance. By definition, Avogadro's number is 6.022 × 10^23 atoms/1 mol. Therefore, we need to multiply the given number of moles by Avogadro's number to get the number of atoms. The correct factor to multiply would be 6.022 × 10^23 atoms/1 mol (choice A).

Question 12

How many atoms of sulfur are present in a 155 g sample of sulfur? [Molar mass: S, 32.06 g/mol]

Accepted Answer

The answer of How many atoms of sulfur are present...

Question 13

What is the mass of a 0.150 mole sample of sulfur?

Accepted Answer

The molar mass of sulfur is 32.06 g/mol. To find the mass of a 0.150 mole sample, we can use the equation: mass = mole x molar mass. Therefore, mass = 0.150 mol x 32.06 g/mol = 4.81 g. The correct answer is E.

Question 14

Cis-platin is a chlorine-containing chemotherapy agent with the formula Pt(NH₃)₂Cl₂.What is the mass of one mole of cis-platin?

Accepted Answer

The answer of Cis-platin is a chlorine-containing chemotherapy agent with...

Question 15

What is the mass of 3.01 mol of sulfur atoms?

Accepted Answer

The answer of What is the mass of 3.01 mol...

Question 16

How is the reaction shown below best classified? 2NaCl(s) + F₂(g) → 2NaF(s) + Cl₂(g)

Accepted Answer

The answer of How is the reaction shown below best...

Question 17

What is the mass of one mole of carbon atoms?

Accepted Answer

The molar mass of an element is equal to the atomic weight of that element in grams per mole. The atomic weight of carbon is 12.01 g/mol, so the mass of one mole of carbon atoms is 12.01 g.

Question 18

Iron reacts with oxygen to form iron(III) oxide according to the chemical equation below.What is the theoretical yield of product when 5.00 grams of Fe react with excess O₂? [Molar masses: Fe, 55.85 g/mol; O, 16.00g/mol] 4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

Accepted Answer

First, we need to find the limiting reactant:
Moles of Fe = 5.00 g / 55.85 g/mol = 0.0893 mol
Moles of O = (excess)
So, we can use the mole ratio from the balanced equation to find the moles of Fe2O3:
0.0893 mol Fe x (1 mol Fe2O3 / 4 mol Fe) = 0.0223 mol Fe2O3
Finally, we can use the molar mass of Fe2O3 to find the theoretical yield:
Theoretical yield = 0.0223 mol Fe2O3 x 159.69 g/mol = 3.56 g
However, since we started with 5.00 g of Fe, which is greater than the theoretical yield of Fe2O3, Fe is the limiting reactant and we need to use its mole ratio instead to find the theoretical yield:
0.0893 mol Fe x (1 mol Fe2O3 / 4 mol Fe) x 159.69 g/mol = 7.15 g

Question 19

The average mass of one atom of copper is 63.55 amu.What is the mass of Avogadro's number of copper atoms?

Accepted Answer

The mass of Avogadro's number of atoms of any element (expressed in grams) is equal to the atomic mass of that element (expressed in atomic mass units, amu). Since the atomic mass of copper is 63.55 amu, the mass of Avogadro's number of copper atoms is 63.55 grams.

Question 20

Lithium oxide can be produced by the reaction shown below.If a manufacturing company wants to make 25.0 g of Li₂O, what mass of Li is necessary? [Molar masses: Li, 6.94 g/mol; O, 16.00 g/mol] 4Li(s) + O₂(g) → 2Li₂O(s)

Accepted Answer

To solve this problem, we need to use stoichiometry. We are given the balanced chemical equation:

4Li(s) + O2(g) → 2Li2O(s)

This equation tells us that 4 moles of Li react with 1 mole of O2 to produce 2 moles of Li2O. Therefore, we can use this relationship to convert between the mass of Li2O and the mass of Li.

First, we need to calculate the molar mass of Li2O:

M(Li2O) = 2M(Li) + M(O) = 2(6.94 g/mol) + 16.00 g/mol = 29.88 g/mol

Next, we can use the following conversion factor:

1 mol Li2O = 4 mol Li

This conversion factor comes from the coefficients in the balanced chemical equation. We can rearrange this equation to solve for the mass of Li:

1 mol Li = 1 mol Li2O ÷ 4
m(Li) = (m(Li2O) ÷ M(Li2O)) × (1 mol Li2O ÷ 4) × M(Li)

Plugging in the given values:

m(Li) = (25.0 g Li2O ÷ 29.88 g/mol) × (1 mol Li2O ÷ 4) × 6.94 g/mol = 11.6 g Li

Therefore, the mass of Li necessary to produce 25.0 g of Li2O is 11.6 g. Answer choice C) is correct.

Quiz 4: Calculations, Chemical Changes, and the Chemical Equation

What mass of sodium hydroxide is necessary to react with a solution containing 73.00 g HCl, according to the chemical equation below? [Molar masses: NaOH, 39.99 g/mol; HCl, 36.45 g/mol] NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

How many iron atoms are present in 0.552 mol of iron?

How is the reaction shown below best classified? Ca(s) + 2HCl(aq) → CaCl₂(g) + H₂(g)

How many moles of Au atoms are present in one ounce of pure gold? [1 oz = 28.4 g]

A sample of sulfur contains 1.81 × 10²⁴ atoms of sulfur.How many moles of sulfur does this represent?

How is the reaction shown below best classified? 2HgO(s) → 2Hg(l) + O₂(g)

Diamond is a pure form of the element carbon.If a 2 carat diamond has a mass of 0.396 g, how many carbon atoms are contained in this diamond?

Dinitrogen monoxide, or laughing gas (N₂O) , is used as a dental anesthetic and as an aerosol propellant.How many molecules of N₂O are present in a 12.6 g sample of the compound?

When the equation below is balanced with the lowest possible whole number coefficients, what is the sum of the coefficients? Ca(s) + HCl(g) → CaCl₂(s) + H₂(g)

To convert a given number of moles into the number of atoms, one would multiply by which of the following factors?

How many atoms of sulfur are present in a 155 g sample of sulfur? [Molar mass: S, 32.06 g/mol]

What is the mass of a 0.150 mole sample of sulfur?

Cis-platin is a chlorine-containing chemotherapy agent with the formula Pt(NH₃) ₂Cl₂.What is the mass of one mole of cis-platin?

What is the mass of 3.01 mol of sulfur atoms?

How is the reaction shown below best classified? 2NaCl(s) + F₂(g) → 2NaF(s) + Cl₂(g)

What is the mass of one mole of carbon atoms?

Iron reacts with oxygen to form iron(III) oxide according to the chemical equation below.What is the theoretical yield of product when 5.00 grams of Fe react with excess O₂? [Molar masses: Fe, 55.85 g/mol; O, 16.00g/mol] 4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

The average mass of one atom of copper is 63.55 amu.What is the mass of Avogadro's number of copper atoms?

Lithium oxide can be produced by the reaction shown below.If a manufacturing company wants to make 25.0 g of Li₂O, what mass of Li is necessary? [Molar masses: Li, 6.94 g/mol; O, 16.00 g/mol] 4Li(s) + O₂(g) → 2Li₂O(s)

Quiz 4: Calculations, Chemical Changes, and the Chemical Equation

What mass of sodium hydroxide is necessary to react with a solution containing 73.00 g HCl, according to the chemical equation below? [Molar masses: NaOH, 39.99 g/mol; HCl, 36.45 g/mol] NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

How many iron atoms are present in 0.552 mol of iron?

How is the reaction shown below best classified? Ca(s) + 2HCl(aq) → CaCl2(g) + H2(g)

How many moles of Au atoms are present in one ounce of pure gold? [1 oz = 28.4 g]

A sample of sulfur contains 1.81 × 1024 atoms of sulfur.How many moles of sulfur does this represent?

How is the reaction shown below best classified? 2HgO(s) → 2Hg(l) + O2(g)

Diamond is a pure form of the element carbon.If a 2 carat diamond has a mass of 0.396 g, how many carbon atoms are contained in this diamond?

Dinitrogen monoxide, or laughing gas (N2O) , is used as a dental anesthetic and as an aerosol propellant.How many molecules of N2O are present in a 12.6 g sample of the compound?

When the equation below is balanced with the lowest possible whole number coefficients, what is the sum of the coefficients? Ca(s) + HCl(g) → CaCl2(s) + H2(g)

To convert a given number of moles into the number of atoms, one would multiply by which of the following factors?

How many atoms of sulfur are present in a 155 g sample of sulfur? [Molar mass: S, 32.06 g/mol]

What is the mass of a 0.150 mole sample of sulfur?

Cis-platin is a chlorine-containing chemotherapy agent with the formula Pt(NH3) 2Cl2.What is the mass of one mole of cis-platin?

What is the mass of 3.01 mol of sulfur atoms?

How is the reaction shown below best classified? 2NaCl(s) + F2(g) → 2NaF(s) + Cl2(g)

What is the mass of one mole of carbon atoms?

Iron reacts with oxygen to form iron(III) oxide according to the chemical equation below.What is the theoretical yield of product when 5.00 grams of Fe react with excess O2? [Molar masses: Fe, 55.85 g/mol; O, 16.00g/mol] 4Fe(s) + 3O2(g) → 2Fe2O3(s)

The average mass of one atom of copper is 63.55 amu.What is the mass of Avogadro's number of copper atoms?

Lithium oxide can be produced by the reaction shown below.If a manufacturing company wants to make 25.0 g of Li2O, what mass of Li is necessary? [Molar masses: Li, 6.94 g/mol; O, 16.00 g/mol] 4Li(s) + O2(g) → 2Li2O(s)

What mass of sodium hydroxide is necessary to react with a solution containing 73.00 g HCl, according to the chemical equation below? [Molar masses: NaOH, 39.99 g/mol; HCl, 36.45 g/mol] NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

How is the reaction shown below best classified? Ca(s) + 2HCl(aq) → CaCl₂(g) + H₂(g)

A sample of sulfur contains 1.81 × 10²⁴ atoms of sulfur.How many moles of sulfur does this represent?

How is the reaction shown below best classified? 2HgO(s) → 2Hg(l) + O₂(g)

Dinitrogen monoxide, or laughing gas (N₂O) , is used as a dental anesthetic and as an aerosol propellant.How many molecules of N₂O are present in a 12.6 g sample of the compound?

When the equation below is balanced with the lowest possible whole number coefficients, what is the sum of the coefficients? Ca(s) + HCl(g) → CaCl₂(s) + H₂(g)

Cis-platin is a chlorine-containing chemotherapy agent with the formula Pt(NH₃) ₂Cl₂.What is the mass of one mole of cis-platin?

How is the reaction shown below best classified? 2NaCl(s) + F₂(g) → 2NaF(s) + Cl₂(g)

Iron reacts with oxygen to form iron(III) oxide according to the chemical equation below.What is the theoretical yield of product when 5.00 grams of Fe react with excess O₂? [Molar masses: Fe, 55.85 g/mol; O, 16.00g/mol] 4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

Lithium oxide can be produced by the reaction shown below.If a manufacturing company wants to make 25.0 g of Li₂O, what mass of Li is necessary? [Molar masses: Li, 6.94 g/mol; O, 16.00 g/mol] 4Li(s) + O₂(g) → 2Li₂O(s)