What is the chemical formula for calcium oxide?

Prepare for the American Water Works Water Treatment Plant Operator Test. Study with multiple choice questions, each with hints and explanations. Get ready to excel!

Multiple Choice

What is the chemical formula for calcium oxide?

Calcium oxide is the oxide of calcium, combining Ca2+ with O2− in a 1:1 ratio to form a neutral compound. That simple 1:1 pairing is what gives the formula CaO. It’s known as quicklime and is produced by heating calcium carbonate to drive off CO2; when you add water to CaO, it becomes calcium hydroxide Ca(OH)2, which helps illustrate the difference between an oxide and a hydroxide. Calcium carbonate CaCO3 is a carbonate, not an oxide, and sodium hydroxide NaOH is a sodium compound, not calcium. So CaO is the correct formula for calcium oxide.

Calcium oxide is the oxide of calcium, combining Ca2+ with O2− in a 1:1 ratio to form a neutral compound. That simple 1:1 pairing is what gives the formula CaO. It’s known as quicklime and is produced by heating calcium carbonate to drive off CO2; when you add water to CaO, it becomes calcium hydroxide Ca(OH)2, which helps illustrate the difference between an oxide and a hydroxide. Calcium carbonate CaCO3 is a carbonate, not an oxide, and sodium hydroxide NaOH is a sodium compound, not calcium. So CaO is the correct formula for calcium oxide.

More practice questions