Question 1

How many grams of iron(II)sulfide is required to make 225 g of sulfuric acid,H₂SO₄? The reactions involved are given below. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

Accepted Answer

First, we need to understand that the final product is sulfuric acid (H₂SO₄). The given reactions show the process of converting iron(II) sulfide (FeS) into sulfuric acid through multiple steps. The molar mass of H₂SO₄ is approximately 98 g/mol, meaning 225 g of H₂SO₄ corresponds to approximately 2.3 moles (225 g / 98 g/mol). The stoichiometry of the first reaction shows that 4 moles of FeS produce 4 moles of SO₂, which eventually leads to the production of 2 moles of H₂SO₄. Therefore, to produce 2.3 moles of H₂SO₄, we need 2.3 moles of FeS, considering the stoichiometry of the entire process. The molar mass of FeS is approximately 88 g/mol, so the required mass of FeS is 2.3 moles * 88 g/mol = 202.4 g, which rounds to 202 g.

Question 2

How many moles of CuO can be produced from 0.900 mol of Cu₂O in the following reaction? 2 Cu₂O(s)+ O₂(g)→ 4 CuO(s)

Accepted Answer

From the balanced chemical equation, we can see that 2 moles of Cu₂O produces 4 moles of CuO. Therefore, 1 mole of Cu₂O produces 2 moles of CuO. 0.900 mol of Cu₂O will produce: 0.900 mol Cu₂O x (2 mol CuO / 1 mol Cu₂O) = 1.80 mol CuO. Therefore, the correct answer is C, 1.80 mol.

Question 3

Aluminum metal reacts with aqueous iron(II)chloride to form aqueous aluminum chloride and iron metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest,whole-number stoichiometric coefficients?

Accepted Answer

The balanced chemical equation is: 
2Al(s) + 3FeCl2(aq) → 2AlCl3(aq) + 3Fe(s) 
The stoichiometric coefficient for aluminum is 2. Therefore, the best choice is B.

Question 4

In the reaction: 4 Zn + K₂Cr₂O₇ + 7 H₂SO₄→ 4 ZnSO₄ + 2 CrSO₄ +K₂SO₄ + 7 H₂O,if the extent of reaction,x,is 0.0393,how many grams of potassium dichromate is required?

Accepted Answer

The answer of In the reaction: 4 Zn + K₂Cr₂O₇...

Question 5

Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.What is the coefficient for sulfuric acid when the equation is balanced using the lowest,whole-number coefficients?

Accepted Answer

The answer of Calcium phosphate reacts with sulfuric acid to...

Question 6

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN₃(s)→ 2 Na(s)+ 3N₂(g) How many moles of N₂ Are produced by the decomposition of 2.88 mol of sodium azide?

Accepted Answer

From the balanced equation, we can see that 2 moles of sodium azide produce 3 moles of N₂. Using dimensional analysis: 2.88 mol NaN₃ x (3 mol N₂/2 mol NaN₃) = 4.32 mol N₂ Therefore, the answer is (C) 4.32.

Question 7

How many moles of BCl₃ are needed to produce 10.0 g of HCl(aq)in the following reaction? BCl₃(g)+ 3 H₂O(l)→ 3 HCl(aq)+ B(OH)₃(aq)

Accepted Answer

To solve the problem, we need to use stoichiometry and conversion of mass to moles. We know that the molar ratio of BCl₃ to HCl is 1:3. Therefore, we can set up a proportion: 10.0 g HCl × (1 mol HCl/36.46 g HCl) × (1 mol BCl₃/3 mol HCl) = 0.0914 mol BCl₃ The first conversion factor is from the molar mass of HCl, and the second conversion factor is from the balanced chemical equation. Therefore, the answer is A) 0.0914 mol.

Question 8

Lithium and nitrogen react to produce lithium nitride: 6 Li_(s) + N₂_(g) → 2 Li₃N_(s) How many moles of lithium nitride are produced when 0.450 mol of lithium react in this fashion?

Accepted Answer

The balanced chemical equation shows that 6 moles of lithium react with nitrogen to produce 2 moles of lithium nitride. Therefore, 0.450 moles of lithium would produce (0.450 moles Li * 2 moles Li3N / 6 moles Li) = 0.150 moles of lithium nitride.

Question 9

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s)+ O₂(g)→ 2 MgO(s) When 4.00 g of magnesium burns,what is the theoretical yield of magnesium oxide?

Accepted Answer

To find the theoretical yield, we need to use stoichiometry. The balanced equation tells us that 2 moles of Mg react with 1 mole of O2 to produce 2 moles of MgO. Using the molar mass of Mg (24.31 g/mol), we can convert the given mass to moles:

4.00 g Mg x (1 mol Mg/24.31 g Mg) = 0.165 mol Mg

Since the reaction ratio is 2:2, the number of moles of MgO produced will be the same as the number of moles of Mg. We can then convert this to mass using the molar mass of MgO (40.30 g/mol):

0.165 mol MgO x (40.30 g MgO/1 mol MgO) = 6.63 g MgO

Therefore, the theoretical yield of MgO is 6.63 g.

Question 10

Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6 Li(s)+ N₂(g)→ 2Li₃N(s) How many moles of lithium are needed to produce 0.60 mol of Li₃N when the reaction is carried out in the presence of excess nitrogen?

Accepted Answer

According to the balanced equation, 6 moles of Li are needed to produce 2 moles of Li₃N. Therefore, to produce 0.60 moles of Li₃N, 1.8 moles of Li are required (0.60 moles Li₃N * 6 moles Li / 2 moles Li₃N = 1.8 moles Li).

Question 11

What are the smallest,whole-number coefficients in front of NO₃^-(aq)and Zn(s)when the following redox equation is balanced? The reaction occurs in acidic solution. ________ NO₃^-(aq)+ ________ Zn(s)→ ________ NO(g)+ ________ Zn²⁺(aq)?

Accepted Answer

In acidic solution, the balanced redox equation is 2 NO₃⁻(aq) + 3 Zn(s) → 2 NO(g) + 3 Zn²⁺(aq).

Question 12

What is the oxidation number change for the manganese atom in the following unbalanced reduction half-reaction: MnO₄^-(aq)+ H⁺(aq)→ Mn²⁺(aq)+ H₂O(l)

Accepted Answer

The answer of What is the oxidation number change for...

Question 13

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s)+ O₂(g)→ 2 MgO(s) How many moles of O₂ Are consumed when 0.770 mol of magnesium burns?

Accepted Answer

According to the balanced equation, 2 moles of Mg react with 1 mole of O2. Therefore, 0.770 moles of Mg will react with 0.770/2 = 0.385 moles of O2.

Question 14

What thickness (in cm)is the silicon block (density = 2.33 g/cm³)that is 2.87 cm wide and long necessary to react with 91.3 g of Cr₂O₃ by the reaction: 3 Si (s)+ 2 Cr₂O₃(s)→ 3 SiO₂(s)+ 4 Cr (l)?

Accepted Answer

To find the thickness, first calculate moles of Cr2O3: 91.3 g / 151.99 g/mol = 0.601 moles. From the reaction, 3 moles of Si react with 2 moles of Cr2O3, so 0.601 moles of Cr2O3 require 0.9015 moles of Si. The mass of Si needed is 0.9015 moles * 28.09 g/mol = 25.32 g. The volume of Si is 25.32 g / 2.33 g/cm³ = 10.86 cm³. The thickness is volume / area = 10.86 cm³ / (2.87 cm * 2.87 cm) = 1.32 cm.

Question 15

306 mL of a 0.208 M solution of silver nitrate will react with 146 mL of a 0.170 M solution of sodium phosphate to produce how many grams of silver phosphate precipitate? The balanced reaction is: 3 AgNO₃ + Na₃PO₄ → Ag₃PO₄ + 3 NaNO₃

Accepted Answer

First, determine the limiting reactant. For AgNO3, moles = 0.306 L * 0.208 mol/L = 0.0637 mol. For Na3PO4, moles = 0.146 L * 0.170 mol/L = 0.0248 mol. The reaction ratio is 3:1 for AgNO3 to Na3PO4, so Na3PO4 is the limiting reactant. Using the molar mass of Ag3PO4 (418.58 g/mol) and the moles of Na3PO4, the mass of Ag3PO4 produced is 0.0248 mol * 418.58 g/mol = 10.38 g, which rounds to 10.4 g, not matching any of the provided options exactly. However, based on the choices given and the closest match, there seems to be a calculation or typographical error in the question or answer choices. Given the context, the correct process was described, but due to a discrepancy in the final matching option, an accurate selection based on the provided answers cannot be made without further clarification. The explanation indicates a calculation aiming towards option D) 10.4 g, but this does not align with the initial selection of A) 8.88 g, suggesting a need for correction either in the calculation or in the interpretation of the question's options.

Question 16

Lithium and nitrogen react to produce lithium nitride: 6 Li(s)+ N₂(g)→ 2Li₃N(s) How many moles of N₂ Are needed to react with 0.500 mol of lithium?

Accepted Answer

The answer of Lithium and nitrogen react to produce lithium...

Question 17

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? ________ CH₁₄O(l)+ ________ O₂(g)→ ________ CO₂(g)+ ________ H₂O(l)

Accepted Answer

The answer of What is the stoichiometric coefficient for oxygen...

Question 18

How many grams of sulfuric acid,H₂SO₄,can be obtained from 400 grams of iron ore if the ore is 80.0% by mass FeS? The reactions involved are given below. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

Accepted Answer

First, calculate the mass of FeS in the ore: 400 g * 80% = 320 g FeS. The molar mass of FeS is approximately 88 g/mol, so there are about 320 g / 88 g/mol = 3.64 mol of FeS. From the first reaction, 4 mol of FeS produce 4 mol of SO2, so 3.64 mol of FeS will produce approximately 3.64 mol of SO2. Following through the reactions, these 3.64 mol of SO2 will eventually yield 3.64 mol of H2SO4. The molar mass of H2SO4 is approximately 98 g/mol, so the mass of H2SO4 produced is 3.64 mol * 98 g/mol = 356.72 g, which rounds to 357 g.

Question 19

How many millilitres of 0.132 mol L^-1 Solution are needed to neutralize 50.00 mL of 0.0789 mol L^-1 NaOH?

Accepted Answer

The answer of How many millilitres of 0.132 mol L^-1...

Question 20

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN₃(s)→ 2 Na(s)+ 3N₂(g) How many grams of sodium azide are required to produce 33.0 g of nitrogen?

Accepted Answer

From the balanced equation, we can see that 2 moles of NaN3 produces 3 moles of N2. This means that 2/3 moles of NaN3 produce 1 mole of N2. 
1 mole of N2 has a mass of 28 g (from the atomic weights of N). 
So to produce 33.0 g of N2, we need (33.0 g) / (28 g/mol) = 1.18 moles of N2. 
Therefore, we need (2/3) x 1.18 = 0.79 moles of NaN3. 
The molar mass of NaN3 is 65 g/mol so we need (0.79 mol) x (65 g/mol) = 51.1 g of NaN3. 
The answer is D.

Quiz 4: Chemical Reactions

How many grams of iron(II) sulfide is required to make 225 g of sulfuric acid,H₂SO₄? The reactions involved are given below. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

How many moles of CuO can be produced from 0.900 mol of Cu₂O in the following reaction? 2 Cu₂O(s) + O₂(g) → 4 CuO(s)

Aluminum metal reacts with aqueous iron(II) chloride to form aqueous aluminum chloride and iron metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest,whole-number stoichiometric coefficients?

In the reaction: 4 Zn + K₂Cr₂O₇ + 7 H₂SO₄→ 4 ZnSO₄ + 2 CrSO₄ +K₂SO₄ + 7 H₂O,if the extent of reaction,x,is 0.0393,how many grams of potassium dichromate is required?

Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.What is the coefficient for sulfuric acid when the equation is balanced using the lowest,whole-number coefficients?

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN₃(s) → 2 Na(s) + 3N₂(g) How many moles of N₂ Are produced by the decomposition of 2.88 mol of sodium azide?

How many moles of BCl₃ are needed to produce 10.0 g of HCl(aq) in the following reaction? BCl₃(g) + 3 H₂O(l) → 3 HCl(aq) + B(OH) ₃(aq)

Lithium and nitrogen react to produce lithium nitride: 6 Li_(s) + N₂_(g) → 2 Li₃N_(s) How many moles of lithium nitride are produced when 0.450 mol of lithium react in this fashion?

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O₂(g) → 2 MgO(s) When 4.00 g of magnesium burns,what is the theoretical yield of magnesium oxide?

Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6 Li(s) + N₂(g) → 2Li₃N(s) How many moles of lithium are needed to produce 0.60 mol of Li₃N when the reaction is carried out in the presence of excess nitrogen?

What are the smallest,whole-number coefficients in front of NO₃^-(aq) and Zn(s) when the following redox equation is balanced? The reaction occurs in acidic solution. NO₃^-(aq) + Zn(s) → NO(g) + Zn²⁺(aq) ?

What is the oxidation number change for the manganese atom in the following unbalanced reduction half-reaction: MnO₄^-(aq) + H⁺(aq) → Mn²⁺(aq) + H₂O(l)

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O₂(g) → 2 MgO(s) How many moles of O₂ Are consumed when 0.770 mol of magnesium burns?

What thickness (in cm) is the silicon block (density = 2.33 g/cm³) that is 2.87 cm wide and long necessary to react with 91.3 g of Cr₂O₃ by the reaction: 3 Si (s) + 2 Cr₂O₃(s) → 3 SiO₂(s) + 4 Cr (l) ?

306 mL of a 0.208 M solution of silver nitrate will react with 146 mL of a 0.170 M solution of sodium phosphate to produce how many grams of silver phosphate precipitate? The balanced reaction is: 3 AgNO₃ + Na₃PO₄ → Ag₃PO₄ + 3 NaNO₃

Lithium and nitrogen react to produce lithium nitride: 6 Li(s) + N₂(g) → 2Li₃N(s) How many moles of N₂ Are needed to react with 0.500 mol of lithium?

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? CH₁₄O(l) + O₂(g) → CO₂(g) + H₂O(l)

How many grams of sulfuric acid,H₂SO₄,can be obtained from 400 grams of iron ore if the ore is 80.0% by mass FeS? The reactions involved are given below. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

How many millilitres of 0.132 mol L^-1 Solution are needed to neutralize 50.00 mL of 0.0789 mol L^-1 NaOH?

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN₃(s) → 2 Na(s) + 3N₂(g) How many grams of sodium azide are required to produce 33.0 g of nitrogen?

Quiz 4: Chemical Reactions

How many grams of iron(II) sulfide is required to make 225 g of sulfuric acid,H2SO4? The reactions involved are given below. 4 FeS + 7O2 → 2 Fe2O3 + 4 SO2 2 SO2 + O2 → 2 SO3 SO3 + H2O → H2SO4

How many moles of CuO can be produced from 0.900 mol of Cu2O in the following reaction? 2 Cu2O(s) + O2(g) → 4 CuO(s)

Aluminum metal reacts with aqueous iron(II) chloride to form aqueous aluminum chloride and iron metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest,whole-number stoichiometric coefficients?

In the reaction: 4 Zn + K2Cr2O7 + 7 H2SO4→ 4 ZnSO4 + 2 CrSO4 +K2SO4 + 7 H2O,if the extent of reaction,x,is 0.0393,how many grams of potassium dichromate is required?

Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.What is the coefficient for sulfuric acid when the equation is balanced using the lowest,whole-number coefficients?

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN3(s) → 2 Na(s) + 3N2(g) How many moles of N2 Are produced by the decomposition of 2.88 mol of sodium azide?

How many moles of BCl3 are needed to produce 10.0 g of HCl(aq) in the following reaction? BCl3(g) + 3 H2O(l) → 3 HCl(aq) + B(OH) 3(aq)

Lithium and nitrogen react to produce lithium nitride: 6 Li(s) + N2(g) → 2 Li3N(s) How many moles of lithium nitride are produced when 0.450 mol of lithium react in this fashion?

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O2(g) → 2 MgO(s) When 4.00 g of magnesium burns,what is the theoretical yield of magnesium oxide?

Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6 Li(s) + N2(g) → 2Li3N(s) How many moles of lithium are needed to produce 0.60 mol of Li3N when the reaction is carried out in the presence of excess nitrogen?

What are the smallest,whole-number coefficients in front of NO3-(aq) and Zn(s) when the following redox equation is balanced? The reaction occurs in acidic solution. ________ NO3-(aq) + ________ Zn(s) → ________ NO(g) + ________ Zn2+(aq) ?

What is the oxidation number change for the manganese atom in the following unbalanced reduction half-reaction: Mn O4- (aq) + H+(aq) → Mn2+(aq) + H2O(l)

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O2(g) → 2 MgO(s) How many moles of O2 Are consumed when 0.770 mol of magnesium burns?

What thickness (in cm) is the silicon block (density = 2.33 g/cm3) that is 2.87 cm wide and long necessary to react with 91.3 g of Cr2O3 by the reaction: 3 Si (s) + 2 Cr2O3 (s) → 3 SiO2 (s) + 4 Cr (l) ?

306 mL of a 0.208 M solution of silver nitrate will react with 146 mL of a 0.170 M solution of sodium phosphate to produce how many grams of silver phosphate precipitate? The balanced reaction is: 3 AgNO3 + Na3PO4 → Ag3PO4 + 3 NaNO3

Lithium and nitrogen react to produce lithium nitride: 6 Li(s) + N2(g) → 2Li3N(s) How many moles of N2 Are needed to react with 0.500 mol of lithium?

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? ________ CH14O(l) + ________ O2(g) → ________ CO2(g) + ________ H2O(l)

How many grams of sulfuric acid,H2SO4,can be obtained from 400 grams of iron ore if the ore is 80.0% by mass FeS? The reactions involved are given below. 4 FeS + 7O2 → 2 Fe2O3 + 4 SO2 2 SO2 + O2 → 2 SO3 SO3 + H2O → H2SO4

How many millilitres of 0.132 mol L-1 Solution are needed to neutralize 50.00 mL of 0.0789 mol L-1 NaOH?

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN3(s) → 2 Na(s) + 3N2(g) How many grams of sodium azide are required to produce 33.0 g of nitrogen?

How many grams of iron(II) sulfide is required to make 225 g of sulfuric acid,H₂SO₄? The reactions involved are given below. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

How many moles of CuO can be produced from 0.900 mol of Cu₂O in the following reaction? 2 Cu₂O(s) + O₂(g) → 4 CuO(s)

In the reaction: 4 Zn + K₂Cr₂O₇ + 7 H₂SO₄→ 4 ZnSO₄ + 2 CrSO₄ +K₂SO₄ + 7 H₂O,if the extent of reaction,x,is 0.0393,how many grams of potassium dichromate is required?

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN₃(s) → 2 Na(s) + 3N₂(g) How many moles of N₂ Are produced by the decomposition of 2.88 mol of sodium azide?

How many moles of BCl₃ are needed to produce 10.0 g of HCl(aq) in the following reaction? BCl₃(g) + 3 H₂O(l) → 3 HCl(aq) + B(OH) ₃(aq)

Lithium and nitrogen react to produce lithium nitride: 6 Li_(s) + N₂_(g) → 2 Li₃N_(s) How many moles of lithium nitride are produced when 0.450 mol of lithium react in this fashion?

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O₂(g) → 2 MgO(s) When 4.00 g of magnesium burns,what is the theoretical yield of magnesium oxide?

Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6 Li(s) + N₂(g) → 2Li₃N(s) How many moles of lithium are needed to produce 0.60 mol of Li₃N when the reaction is carried out in the presence of excess nitrogen?

What are the smallest,whole-number coefficients in front of NO₃^-(aq) and Zn(s) when the following redox equation is balanced? The reaction occurs in acidic solution. NO₃^-(aq) + Zn(s) → NO(g) + Zn²⁺(aq) ?

What is the oxidation number change for the manganese atom in the following unbalanced reduction half-reaction: MnO₄^-(aq) + H⁺(aq) → Mn²⁺(aq) + H₂O(l)

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O₂(g) → 2 MgO(s) How many moles of O₂ Are consumed when 0.770 mol of magnesium burns?

What thickness (in cm) is the silicon block (density = 2.33 g/cm³) that is 2.87 cm wide and long necessary to react with 91.3 g of Cr₂O₃ by the reaction: 3 Si (s) + 2 Cr₂O₃(s) → 3 SiO₂(s) + 4 Cr (l) ?

306 mL of a 0.208 M solution of silver nitrate will react with 146 mL of a 0.170 M solution of sodium phosphate to produce how many grams of silver phosphate precipitate? The balanced reaction is: 3 AgNO₃ + Na₃PO₄ → Ag₃PO₄ + 3 NaNO₃

Lithium and nitrogen react to produce lithium nitride: 6 Li(s) + N₂(g) → 2Li₃N(s) How many moles of N₂ Are needed to react with 0.500 mol of lithium?

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? CH₁₄O(l) + O₂(g) → CO₂(g) + H₂O(l)

How many grams of sulfuric acid,H₂SO₄,can be obtained from 400 grams of iron ore if the ore is 80.0% by mass FeS? The reactions involved are given below. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

How many millilitres of 0.132 mol L^-1 Solution are needed to neutralize 50.00 mL of 0.0789 mol L^-1 NaOH?

Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements: 2NaN₃(s) → 2 Na(s) + 3N₂(g) How many grams of sodium azide are required to produce 33.0 g of nitrogen?