Chemistry IX. Stoichiomestry

2NaClO₃ (s) → 2NaCl (s) + 3O₂ (g)

12.00 moles of NaClO₃ will produce how many grams of O₂?

NaClO₃ = 106.44 g/mol ; O₂ = 32.00 g/mol

• 256 g of O₂

• 576 g of O₂

• 288 g of O₂

• 384 g of O₂

From the reaction: B₂H₆ + 3O₂ -->2 HBO₂ + 2 H₂O

What mass of O₂ will be needed to burn 36.1 g of B₂H₆?

B₂H₆ = 27.68 g/mol

• 13.8 g O₂

• 3.91 mol of O₂

• 125 g O₂

• 41.7 g O₂

18.26 mL of a 1.50 mol/L hydrochloric acid reacts with magnesium hydroxide. Calculate the mass of magnesium hydroxide needed for the reaction.

Mg(OH)₂ + 2 HCl -> 2 H₂O + MgCl₂

Mg(OH)₂ = 58.33 g/mol ; HCl = 36.46 g/mol

• 4.68 g Mg(OH)₂

• 0.799 g Mg(OH)₂

• 0.0274 Mg(OH)₂

• 1.60 g Mg(OH)₂

Balance this reaction: ____ RbNO₃ + ____ BeF₂ ----> ____ Be(NO₃)₂ + ____ RbF

• 1,1,1,1
• 1,2,1,1
• 2,1,1,2
• 2,1,2,1

When 12 moles of O₂ reacts with 1.1 mole of C₁₀H₈ what is the limiting reactant?  C₁₀H₈ + 12 O₂ --> 10 CO₂ + 4 H₂O

• Oxygen
• C₁₀H₈
• Water
• Carbon Dioxide

What is the percent yield of the following reaction if 145g of P₂O₅ reacts with 40 grams of water, but you only collected 112 grams of phosphoric acid (MW 98g/mol)?  3 H₂O + P₂O₅ -> 2H₃PO₄

• 80%
• 85%
• 77%
• 58%

For the reaction represented by the equation Cl₂ + 2KBr → Br₂ + 2KCl, how many grams of potassium chloride can be produced from 356 grams potassium bromide? (atomic masses: K=39 Cl=35.5 Br=80)

• 749 g
• 223 g

• 479 g
• 814 g

2Al + 3H₂SO₄ -> Al₂(SO₄)₃ + 3H₂ How many grams of aluminum sulfate (MW 342g/mol) would be formed if 250g H₂SO₄ (MW 98g/mol) completely reacted with aluminum?

• 0.85 g
• 291 g

• 450 g
• 870 g

Use the following equation: 2NaOH(aq) + H₂SO₄(aq) --> 2H₂O(l) + Na₂SO₄(aq) How many grams of sodium sulfate (MW 142g/mol) will be formed if you start with 200 grams of sodium hydroxide (MW 40g/mol) ?

• 150 g Na₂SO₄

• 593 g Na₂SO₄

• 330 g Na₂SO₄

• 355 g Na₂SO₄

___KNO₃ → ___KNO₂ + ___O₂

What coefficients are needed to balance the reaction?

• 2, 2, 1

• 2, 3, 2

• 1, 2, 2

• 1, 3, 1