To determine which statement best describes the equation [tex]\( CaCO_3 + 2HCl \rightarrow CaCl_2 + CO_2 + H_2O \)[/tex], we should analyze the components of the chemical reaction step-by-step.
### Step-by-Step Analysis:
1. Identify the reactants and products:
- Reactants: These are the substances present before the reaction occurs. They are found on the left side of the chemical equation. In this equation, the reactants are [tex]\( CaCO_3 \)[/tex] (calcium carbonate) and [tex]\( HCl \)[/tex] (hydrochloric acid).
- Products: These are the substances formed as a result of the reaction. They are found on the right side of the chemical equation. In this equation, the products are [tex]\( CaCl_2 \)[/tex] (calcium chloride), [tex]\( CO_2 \)[/tex] (carbon dioxide), and [tex]\( H_2O \)[/tex] (water).
2. Match statements with identified reactants and products:
- Statement 1: [tex]\( CaCO_3 \)[/tex] is a reactant; it is present before the reaction occurs.
- This statement correctly identifies [tex]\( CaCO_3 \)[/tex] as a reactant, which we found on the left side of the equation.
- Statement 2: [tex]\( CaCl_2 \)[/tex] is a reactant; it is present before the reaction occurs.
- This is incorrect because [tex]\( CaCl_2 \)[/tex] is a product found on the right side of the equation.
- Statement 3: [tex]\( CO_2 \)[/tex] is a reactant because it is most likely a gas.
- This is incorrect because [tex]\( CO_2 \)[/tex] is a product, even though it is indeed most likely a gas. Being a gas does not necessarily mean it is a reactant.
- Statement 4: [tex]\( H_2O \)[/tex] is a reactant because it is most likely a liquid.
- This is incorrect because [tex]\( H_2O \)[/tex] is a product, even though it is most likely a liquid. Being a liquid does not necessarily mean it is a reactant.
Given the analysis:
- Statement 1 is correct as it accurately describes [tex]\( CaCO_3 \)[/tex] as a reactant present before the reaction occurs.
Therefore, the best statement that describes the equation [tex]\( CaCO_3 + 2HCl \rightarrow CaCl_2 + CO_2 + H_2O \)[/tex] is:
[tex]\[ \boxed{1} \][/tex]
[tex]\[ \text{"CaCO}_3 \text{ is a reactant; it is present before the reaction occurs."} \][/tex]
