how many grams of sodium iodide must be used to produce 30.2 g of iodine?
The correct answer and explanation is:
To solve this problem, we need to use stoichiometry to find the number of grams of sodium iodide (NaI) required to produce 30.2 g of iodine (I2).
- Write the balanced chemical equation:
The reaction between sodium iodide and chlorine to produce iodine is:
2NaI+Cl2→I2+2NaCl2NaI + Cl_2 \rightarrow I_2 + 2NaCl
This equation shows that 2 moles of NaI produce 1 mole of I2.
- Determine the molar masses:
- Molar mass of I2 = 2×126.90 g/mol=253.80 g/mol2 \times 126.90 \, g/mol = 253.80 \, g/mol
- Molar mass of NaI = 22.99 g/mol (Na)+126.90 g/mol (I)=149.89 g/mol22.99 \, g/mol \, (Na) + 126.90 \, g/mol \, (I) = 149.89 \, g/mol
- Convert grams of iodine to moles:
To convert 30.2 g of iodine (I2) to moles, use the formula: moles of I2=grams of I2molar mass of I2\text{moles of I}_2 = \frac{\text{grams of I}_2}{\text{molar mass of I}_2} moles of I2=30.2 g253.80 g/mol=0.119 mol\text{moles of I}_2 = \frac{30.2 \, g}{253.80 \, g/mol} = 0.119 \, mol
- Use the stoichiometric ratio to find moles of NaI:
From the balanced equation, 2 moles of NaI produce 1 mole of I2. Therefore, the moles of NaI needed are: moles of NaI=0.119 mol×2 mol NaI1 mol I2=0.238 mol NaI\text{moles of NaI} = 0.119 \, mol \times \frac{2 \, mol \, NaI}{1 \, mol \, I_2} = 0.238 \, mol \, NaI
- Convert moles of NaI to grams:
Now, convert moles of NaI to grams by multiplying by the molar mass of NaI: grams of NaI=0.238 mol×149.89 g/mol=35.7 g\text{grams of NaI} = 0.238 \, mol \times 149.89 \, g/mol = 35.7 \, g
Final Answer:
To produce 30.2 g of iodine, you will need 35.7 grams of sodium iodide.
Explanation:
In this problem, stoichiometry is used to convert the given amount of iodine into sodium iodide. The key steps are determining the molar relationships from the balanced chemical equation, converting grams to moles, using the molar ratio to find the moles of NaI required, and then converting moles of NaI back into grams. Each step relies on the principle that the reactants and products in a chemical reaction are related by fixed proportions, known as the mole ratio.