Question

calculating mass quick check
a student knows the mass of one of the reactants of a chemical reaction and wants to calculate the mass of one of the products of the reaction. which process should the student follow? (1 point)
divide the mass of the reactant by its molar mass to find the number of moles of the reactant. use the chemical equation to find the number of moles of the product. divide the number of moles of the product by its molar mass to find the mass of the product.
multiply the mass of the reactant by its molar mass to find the number of moles of the reactant. use the chemical equation to find the number of moles of the product. divide the number of moles of the product by its molar mass to find the mass of the product.
multiply the mass of the reactant by its molar mass to find the number of moles of the reactant. use the chemical equation to find the number of moles of the product. multiply the number of moles of the product by its molar mass to find the mass of the product.
divide the mass of the reactant by its molar mass to find the number of moles of the reactant. use the chemical equation to find the number of moles of the product. multiply the number of moles of the product by its molar mass to find the mass of the product.

Explanation:

Step1: Calculate moles of reactant

The formula for calculating the number of moles \(n\) is \(n=\frac{m}{M}\), where \(m\) is the mass and \(M\) is the molar mass. So, to find the moles of the reactant, we divide the mass of the reactant by its molar mass (\(n_{reactant}=\frac{m_{reactant}}{M_{reactant}}\)).

Step2: Relate moles of reactant and product

Using the stoichiometry from the balanced chemical equation (e.g., if \(aA + bB
ightarrow cC + dD\), the mole ratio \(\frac{n_{C}}{n_{A}}=\frac{c}{a}\)), we find the moles of the product (\(n_{product}=n_{reactant}\times\) mole - ratio from the equation).

Step3: Calculate mass of product

Since \(m = n\times M\), to get the mass of the product, we multiply the number of moles of the product by its molar mass (\(m_{product}=n_{product}\times M_{product}\)).

Answer:

Divide the mass of the reactant by its molar mass to find the number of moles of the reactant. Use the chemical equation to find the number of moles of the product. Multiply the number of moles of the product by its molar mass to find the mass of the product.