Question

balance of atoms quick check
one molecule of calcium oxide, cao, and one molecule of carbon dioxide, co₂, combine in a chemical reaction to form one substance. given that matter is neither created nor destroyed, which chemical formula identifies the product of this reaction? (1 point)
○ caco₃
○ caco₂
○ ca₂co₃
○ ca₂o₃

Explanation:

Step1: Count atoms in reactants

In CaO, there is 1 Ca and 1 O. In CO₂, there is 1 C and 2 O. So in total, we have 1 Ca, 1 C and 3 O.

Step2: Check product options

We need a formula with 1 Ca, 1 C and 3 O.

• CaCO₃ has 1 Ca, 1 C and 3 O.
• CaCO₂ has 1 Ca, 1 C and 2 O.
• Ca₂CO₃ has 2 Ca, 1 C and 3 O.
• Ca₂O₃ has 2 Ca and 3 O.

Answer:

CaCO₃