To solve the problems, we need to use the formula for molarity:
\[
\text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liters of solution}}
\]
Problem 1:
0.5 moles of sodium chloride is dissolved to make 0.05 liters of solution.
-
Given:
- Moles of solute = 0.5 mol
- Volume of solution = 0.05 L
-
Formula:
\[
\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}
\]
-
Substitute the values:
\[
\text{Molarity} = \frac{0.5 \, \text{mol}}{0.05 \, \text{L}}
\]
-
Calculate:
\[
\text{Molarity} = \frac{0.5}{0.05} = 10 \, \text{M}
\]
Answer for Problem 1:
\[
\boxed{10 \, \text{M}}
\]
---
Problem 2:
0.5 grams of sodium chloride is dissolved to make 0.05 liters of solution.
-
Given:
- Mass of solute = 0.5 g
- Volume of solution = 0.05 L
- Molar mass of sodium chloride (NaCl) = 58.44 g/mol
-
Step 1: Convert mass to moles using the molar mass.
\[
\text{Moles of NaCl} = \frac{\text{mass of NaCl}}{\text{molar mass of NaCl}}
\]
\[
\text{Moles of NaCl} = \frac{0.5 \, \text{g}}{58.44 \, \text{g/mol}}
\]
\[
\text{Moles of NaCl} \approx 0.00856 \, \text{mol}
\]
-
Step 2: Calculate molarity using the formula.
\[
\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}
\]
\[
\text{Molarity} = \frac{0.00856 \, \text{mol}}{0.05 \, \text{L}}
\]
-
Calculate:
\[
\text{Molarity} \approx \frac{0.00856}{0.05} \approx 0.1712 \, \text{M}
\]
Answer for Problem 2:
\[
\boxed{0.171 \, \text{M}}
\]
---
Problem 3:
0.5 grams of sodium chloride is dissolved to make 0.05 mL of solution.
-
Given:
- Mass of solute = 0.5 g
- Volume of solution = 0.05 mL
- Molar mass of sodium chloride (NaCl) = 58.44 g/mol
-
Step 1: Convert mass to moles using the molar mass.
\[
\text{Moles of NaCl} = \frac{\text{mass of NaCl}}{\text{molar mass of NaCl}}
\]
\[
\text{Moles of NaCl} = \frac{0.5 \, \text{g}}{58.44 \, \text{g/mol}}
\]
\[
\text{Moles of NaCl} \approx 0.00856 \, \text{mol}
\]
-
Step 2: Convert volume from mL to L.
\[
\text{Volume in L} = \frac{\text{Volume in mL}}{1000}
\]
\[
\text{Volume in L} = \frac{0.05 \, \text{mL}}{1000} = 0.00005 \, \text{L}
\]
-
Step 3: Calculate molarity using the formula.
\[
\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}
\]
\[
\text{Molarity} = \frac{0.00856 \, \text{mol}}{0.00005 \, \text{L}}
\]
-
Calculate:
\[
\text{Molarity} \approx \frac{0.00856}{0.00005} \approx 171.2 \, \text{M}
\]
Answer for Problem 3:
\[
\boxed{171.2 \, \text{M}}
\]
---
Final Answers:
1. \(\boxed{10 \, \text{M}}\)
2. \(\boxed{0.171 \, \text{M}}\)
3. \(\boxed{171.2 \, \text{M}}\)
Parent Tip: Review the logic above to help your child master the concept of chemistry solutions worksheet.
