Physical Science 7.1

Multiple Choice

Which of the following is a balanced chemical equation for the reaction of aluminium and ammonium perchlorate?

• Al + NH₄ClO₄ —› Al₂O₃ + NH₄Cl

• 4Al + 3NH₄ClO₄ —› 4Al₂O₃  + 3NH₄Cl

• 8Al + NH₄ClO₄ —› 4Al₂O₃ + NH₄Cl

• 8Al + 3NH₄ClO₄ —› 4Al₂O₃ + 3NH₄Cl

Multiple Choice

How many moles of NaCl (molar mass = 58.5) are there in a 10-gram sample?

• 58 mol

• 5.8 mol

• 0.17 mol

• 0.28 mol

Multiple Choice

In the reaction shown below, how many grams of hydrogen are produced when 10 moles of potassium react with water?

2K + 2H₂O —› 2KOH + H₂

• 2.5 g

• 5 g

• 10 g

• 20 g

Multiple Choice

In the chemical equation below, the reactants are carbon dioxide and water.

CH₄ + 2O₂ —› CO₂  +2H₂O

• True

• False