Question

this passage describes a chemical reaction. read the passage. then, answer the question below. when tap water contains high levels of calcium, a substance called calcium carbonate (caco₃) can build up at the mouths of water faucets. this buildup, called limescale, can prevent water from flowing through a faucet properly. to remove the calcium carbonate, you can scrub the faucet with citric acid (c₆h₈o₇). citric acid combines with calcium carbonate to form calcium citrate (ca₃c₁₂h₁₀o₁₄), carbon dioxide gas (co₂), and water (h₂o). the calcium citrate washes away easily, allowing water to flow through the faucet again. in the chemical reaction described in the passage, which of the following are reactants? select all that apply. calcium carbonate (caco₃) carbon dioxide (co₂) water (h₂o) citric acid (c₆h₈o₇)

Explanation:

Step1: Define reactants

Reactants are substances that participate in a chemical - reaction and are present at the start.

Step2: Identify from the passage

The passage states that citric acid combines with calcium carbonate to form products. So, calcium carbonate ($CaCO_3$) and citric acid ($C_6H_8O_7$) are reactants. Water ($H_2O$) and carbon dioxide ($CO_2$) are products of the reaction.

Answer:

A. calcium carbonate ($CaCO_3$), D. citric acid ($C_6H_8O_7$)