Lesson 4. (6+7)

What is the chemical formula of water?

• H2O
• NaCl
• CO2
• H2O2

What is the chemical formula of methane?

• H2O

• CH4

• CO

• H2O2

In the equation C + O₂ → CO₂, what are the reactants?

• C and O₂

• C and H₂O

• O₂ and CO

• C CO

In the reaction X +Y-----> A + B, reactant X has 12g, reactant Y has 3 g and product B has 5g. How many grams should product A have?

• 6g
• 8g
• 10g
• 12g

The equation is balanced: aCO + O₂ → aCO₂. What is the value of a?

• 1
• 2
• 3
• 4
• 5

What is the balanced equation for the combustion of propane (C₃H₈)?

• C₃H₈ + 3O₂ → 3CO₂ + 3H₂O

• C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

• C₃H₈ + 4O₂ → 3CO₂ + 4H₂O

• C₃H₈ + 2O₂ → 3CO₂ + 2H₂O