Unit 5 Review Game

Balance the Equation & label the kind of reaction

100

N₂+H₂→NH₃

N₂+3H₂→2NH₃

_Synthesis 

200

CaCO₃→CaO+CO₂

CaCO₃→CaO+CO₂ (No changes- balanced)

Decomposition 

300

Fe+CuSO₄→FeSO₄+Cu

 Fe+CuSO₄→FeSO₄+Cu (no changes- balanced)

single displacement

400

BaCl₂+Na₂CO₃→BaCO₃+NaCl

BaCl₂+Na₂CO₃→BaCO₃+ 2NaCl

double displacement

500

C₂H₆+O₂→CO₂+H₂O

2C₂H₆+7O₂→4CO₂+6H₂O

Combustion 

Stoichiometry

100

How many moles are in 36 g of C?

3 moles

200

How many atoms are in 3 moles of Mg?

3× (6.022×10²³) = 1.8066×10²⁴ atoms

300

A sample of iron weighs 112 g and contains 2.0×10²⁴ 2.0. Determine its molar mass.

33.73 g/mol

400

N₂+3H₂→2NH₃

If 2 moles of N₂ react with excess H₂, how many moles of NH₃ are produced?

• Mole ratio: 1 N₂ : 2 NH₃
• Given: 2 moles N₂

Moles of NH₃=2×2=4 moles NH₃ 

500

2Na+Cl₂→2NaCl

If 5 moles of Na react with Cl₂, how many moles of NaCl are formed?

• Mole ratio: 2 Na : 2 NaCl → 1:1
• Given: 5 moles Na

Moles of NaCl=5 moles NaCl

Stoichiometry 2

100

Calculate the molar mass of NHO₃

14 + 1 +(3×16)=1+14+48=63 g/mol

200

How many moles are in a sample that contains 56 g of N₂.

56 g/ 28g = 2 mol

300

How many atoms are present in a sample contains 73 g of HCl ?

• Moles: 73 / 36.5 = 2 mol
• Molecules: 2 × 6.022×10²³ = 1.204×10²⁴

400

2C₂H₆+7O₂→4CO₂+6H₂O

If 3 moles of C₂H₆ are burned completely, how many moles of CO₂ are produced?

• Mole ratio: 2 C₂H₆ : 4 CO₂ → 1:2
• Given: 3 moles C₂H₆

Moles of CO₂=3×2=6 moles CO₂

500

2H₂O→2H₂+O₂

If 9 grams of water (H₂O) decompose completely: Find the total number of H atoms produced. 

1× 6.022×10²³ = 6.022×10²³ H atoms

Mass Percents & Molecular & empirical formulas

100

Calculate the mass percent of Oxygen in H₂SO₄  

• Molar mass H₂SO₄ = 2×1 + 32 + 4×16 = 98 g/mol
• Mass of O = 4×16 = 64 g

65.31%

200

A compound contains 40.0% C, 6.7% H, and 53.3% O. Its molar mass is 180 g/mol. Determine the empirical formula. 

• Moles: C = 40 ÷ 12 = 3.33; H = 6.7 ÷ 1 = 6.7; O = 53.3 ÷16 = 3.33

• Divide by smallest: C:1, H:2, O:1 → Empirical formula = CH₂O

300

A compound contains 38.7% C, 9.7% H, and 51.6% O. Its molar mass is 60 g/mol. Determine the molecular formula. 

• Moles: C = 38.7 ÷ 12 ≈ 3.225; H = 9.7 ÷1 ≈ 9.7; O = 51.6 ÷16 ≈ 3.225

• Divide by smallest: C:1, H:3, O:1 → Empirical = CH₃O

• Empirical mass = 12 + 3 +16 = 31 g/mol

• Molecular formula = 60 ÷31 ≈ 2 → C₂H₆O

400

A compound contains 71.65% Cl and 28.35% O. Its molar mass is 142.5 g/mol. Determine the empirical formula.

• Moles: Cl =71.65 ÷35.5 ≈2.02; O=28.35 ÷16 ≈1.77
• Divide by smallest: Cl ≈1.14, O ≈1 → multiply all by ~7 → Cl₈O₆? Actually simplify: Cl:O ≈2:1 → Empirical = Cl₂O

500

A compound contains 71.65% Cl and 28.35% O. Its molar mass is 142.5 g/mol. Determine the molecular formula.

• Moles: Cl =71.65 ÷35.5 ≈2.02; O=28.35 ÷16 ≈1.77
• Divide by smallest: Cl ≈1.14, O ≈1 → multiply all by ~7 → Cl₈O₆? Actually simplify: Cl:O ≈2:1 → Empirical = Cl₂O
• Empirical mass = 2×35.5 +16 = 87+16=87 g/mol
• Molecular formula = 142.5 ÷87 ≈1.64 → multiply formula by 2 → Cl₄O₂ → simplified Cl₂O

Random

100

States that if a stress is applied to a system at equilibrium, the system shifts in the direction that relieves the stress.

Le Chatelier's Principle

200

 The reactant of which there is not enough; when it is used up, the reaction stops and no new product is formed

Limiting Reagent 

300

If you removed a product from a system at equilibrium- in what direction would the reaction move?

right- producing more reactants.

400

If you added heat to a combustion reaction- in which direction would the reaction move?

move towards the reactants (left)

500

The reaction of hydrogen gas with oxygen gas produces water:

2H₂+O₂→2H₂O₂

If 4.0 grams of H₂ react with excess O₂, the theoretical yield of H₂O is calculated to be 36 grams. However, the actual yield obtained in the lab is 30 grams.

What is the percent yield?

83.3%