Limiting Reagents I Answer Key (CHEM 1405)

Back to Chemistry 1405 Practice Problems

Balance the equations, then solve for the required substance using dimensional analysis.

1) Nitrogen and oxygen react to form dinitrogen monoxide.

2N₂ + O₂ 2N₂O

If 7.4 grams of nitrogen reacts, how many grams of dinitrogen monoxide is produced?

Limiting Reagent Theoretical Yield
$LaTeX: 7.4gN_2\times(\frac{1molN_2}{28.02gN_2})\times(\frac{2molN_2O}{2molN_2})\times(\frac{44.02gN_2O}{1molN_2O})=$ $7.4gN_2\times(\frac{1molN_2}{28.02gN_2})\times(\frac{2molN_2O}{2molN_2})\times(\frac{44.02gN_2O}{1molN_2O})=$ 12g N₂O

If 6.8 grams of oxygen reacts, how many grams of dinitrogen monoxide is produced?

$LaTeX: 6.8gO_2\times(\frac{1molO_2}{32.00gO_2})\times(\frac{2molN_2O}{1molO_2})\times(\frac{44.02gN_2O}{1molN_2O})=$ $6.8gO_2\times(\frac{1molO_2}{32.00gO_2})\times(\frac{2molN_2O}{1molO_2})\times(\frac{44.02gN_2O}{1molN_2O})=$ 19g N₂O

Based on the information above, which would be the limiting reagent? _____N₂_____

2) Potassium and chlorine combined to make potassium chloride.

2K + Cl₂ 2KCl

If 0.14 g potassium reacts, how many grams of KCl is produced?

Limiting Reagent Theoretical Yield
$LaTeX: 0.14gK\times(\frac{1molK}{39.10gK})\times(\frac{2molKCl}{2molK})\times(\frac{74.55gKCl}{1molKCl})=$ $0.14gK\times(\frac{1molK}{39.10gK})\times(\frac{2molKCl}{2molK})\times(\frac{74.55gKCl}{1molKCl})=$ 0.27g KCl

If 0.23 g chlorine reacts, how many grams of KCl is produced?

$LaTeX: 0.23gCl_2\times(\frac{1molCl_2}{70.90gCl_2})\times(\frac{2molKCl}{1molCl_2})\times(\frac{74.55gKCl}{1molKCl})=$ $0.23gCl_2\times(\frac{1molCl_2}{70.90gCl_2})\times(\frac{2molKCl}{1molCl_2})\times(\frac{74.55gKCl}{1molKCl})=$ 0.48g KCl

Based on the information above, which would be the limiting reagent? _____K_____

3) Aluminum reacts with oxygen to yield aluminum oxide.

4Al + 3O₂ 2Al₂O₃

If you have 14.5 g of aluminum, how many grams of aluminum oxide is produced?

$LaTeX: 14.5gAl\times(\frac{1molAl}{26.98gAl})\times(\frac{2molAl_2O_3}{4molAl})\times(\frac{101.96gAl_2O_3}{1molAl_2O_3})=$ $14.5gAl\times(\frac{1molAl}{26.98gAl})\times(\frac{2molAl_2O_3}{4molAl})\times(\frac{101.96gAl_2O_3}{1molAl_2O_3})=$ 27.4g Al₂O₃

If you have 7.5 g of oxygen, how many grams of aluminum oxide is produced?

Limiting Reagent Theoretical Yield
$LaTeX: 7.5gO_2\times(\frac{1molO_2}{32.00gO_2})\times(\frac{2molAl_2O_3}{3molO_2})\times(\frac{101.96gAl_2O_3}{1molAl_2O_3})=$ $7.5gO_2\times(\frac{1molO_2}{32.00gO_2})\times(\frac{2molAl_2O_3}{3molO_2})\times(\frac{101.96gAl_2O_3}{1molAl_2O_3})=$ 16g O₂

Based on the information above, which would be the limiting reagent? _____O₂_____

4) Copper II sulfide reacts with oxygen to produce copper II oxide and sulfur dioxide.

2CuS + 3O₂ 2CuO + 2SO₂

If you have 18.7 g of copper II sulfide, how many grams of copper II oxide is produced?

Limiting Reagent Theoretical Yield
$LaTeX: 18.7gCuS\times(\frac{1molCuS}{95.62gCuS})\times(\frac{2molCuO}{2molCuS})\times(\frac{79.55molCuO}{1molCuO})=$ $18.7gCuS\times(\frac{1molCuS}{95.62gCuS})\times(\frac{2molCuO}{2molCuS})\times(\frac{79.55molCuO}{1molCuO})=$ 15.6g CuO

If you have 12.0 g of oxygen gas, how many grams of copper II oxide is produced?

$LaTeX: 12.0gO_2\times(\frac{1molO_2}{32.00gO_2})\times(\frac{2molCuO}{3molO_2})\times(\frac{79.55molCuO}{1molCuO})=$ $12.0gO_2\times(\frac{1molO_2}{32.00gO_2})\times(\frac{2molCuO}{3molO_2})\times(\frac{79.55molCuO}{1molCuO})=$ 19.9g CuO

Based on the information above, which would be the limiting reagent? _____CuS_____

5) Nitrogen and hydrogen react to produce ammonia (NH₃).

N₂ + 3H₂ 2NH₃

If you have 2.6 g of nitrogen, how many grams of ammonia is produced?

Limiting Reagent Theoretical Yield
$LaTeX: 2.6gN_2\times(\frac{1molN_2}{28.02gN_2})\times(\frac{2molNH_3}{1molN_2})\times(\frac{17.04gNH_3}{1molNH_3})=$ $2.6gN_2\times(\frac{1molN_2}{28.02gN_2})\times(\frac{2molNH_3}{1molN_2})\times(\frac{17.04gNH_3}{1molNH_3})=$ 3.2g NH₃

If you have 1.7 g of hydrogen, how many grams of ammonia is produced?

$LaTeX: 1.7gH_2\times(\frac{1molH_2}{2.02gH_2})\times(\frac{2molNH_3}{3molH_2})\times(\frac{17.04gNH_3}{1molNH_3})=$ $1.7gH_2\times(\frac{1molH_2}{2.02gH_2})\times(\frac{2molNH_3}{3molH_2})\times(\frac{17.04gNH_3}{1molNH_3})=$ 9.6g NH₃

Based on the information above, which would be the limiting reagent? _____N₂_____

6) Hydrogen chloride is made by reacting sodium chloride with aqueous hydrogen sulfate.

2NaCl + H₂SO₄ Na₂SO₄ + 2HCl

If you have 30.0 g of sodium chloride, how many grams of hydrogen chloride are produced?

$LaTeX: 30.0gNaCl\times(\frac{1molNaCl}{58.44gNaCl})\times(\frac{2molHCl}{2molNaCl})\times(\frac{36.46gHCl}{1molHCl})=$ $30.0gNaCl\times(\frac{1molNaCl}{58.44gNaCl})\times(\frac{2molHCl}{2molNaCl})\times(\frac{36.46gHCl}{1molHCl})=$ 18.7g HCl

If you have 2.59 g of hydrogen sulfate, how many grams of hydrogen chloride are produced?

Limiting Reagent Theoretical Yield
$LaTeX: 2.59gH_2SO_4\times(\frac{1molH_2SO_4}{98.08gH_2SO_4})\times(\frac{2molHCl}{1molH_2SO_4})\times(\frac{36.46gHCl}{1molHCl})=$ $2.59gH_2SO_4\times(\frac{1molH_2SO_4}{98.08gH_2SO_4})\times(\frac{2molHCl}{1molH_2SO_4})\times(\frac{36.46gHCl}{1molHCl})=$ 1.93g HCl

Based on the information above, which would be the limiting reagent? _____H₂SO₄_____