Answer:
Step-by-step explanation:
To solve this problem, we must use stoichiometry: the calculation of reactants and products in a chemical reaction using ratios.
1. Analyze the Reaction
Check the coefficients, which indicate the moles required for the reaction. 2 moles of sodium (Na) and 1 mole of chlorine (Cl₂) produces 2 moles of sodium chloride (NaCl).
2. Set Up Ratios.
We are asked to find the grams of NaCl produced when 0.548 moles of Na react with excess chlorine.
We need 2 ratios: 1 for finding the moles of NaCl produced and 1 for converting to grams.
The first ratio is found using the coefficients. Since there is excess chlorine, we only need to focus on the sodium and sodium chloride. According to their coefficients, 2 moles of Na produce 2 moles of NaCl. This is the first ratio.
The second ratio uses the molar mass. Since we are solving for the grams of NaCl, we have to find its molar mass.
First, locate these values on the Periodic Table for the individual elements.
- Na: 22.989769 g/mol
- Cl: 35.45 g/mol
There is 1 of each atom in 1 molecule, so we can add these values.
Use this value as the second ratio.
3. Calculate
Make 1 expression using the 2 ratios and the initial value of moles.
Flip the ratios so the correct units cancel out.
Multiply. Note that the moles of Na (units) cancel and the moles of NaCl (units). cancel.
The original value of moles has 3 significant figures, so our answer must have the same. For the number we found, that is the tenth place.
The 2 in the hundredth place tells us to leave the 0.
0.548 moles of sodium react with excess chlorine to produce 32.0 grams of sodium chloride.