Answer:
Explanation:
1) Write the molecular chemical equation
- MgCl₂ (aq) + 2AgNO₃ (aq) → 2AgCl(s) + Mg(NO₃)₂ (aq)
2) Mole ratios
- 1 mol MgCl₂ : 2 mol AgNO₃ : 2 mol AgCl : 1 mol Mg(NO₃)₂
3) Number of moles of MgCl₂
- Molarity, M = 0.143 M
- volume = V = 22 mL = 0.022 liter
- number of moles, n
- M = n / V (in liter) ⇒ n - M × V = 0.143 M × 0.022 liter = 0.033146 mol
4) Number of moles of AgNO₃
Set a proportion, using the appropiate mole ratio and the number of moles of MgCl₂:
- 1 mol MgCl₂ / 2 mol AgNO₃ = 0.033146 mol MgCl₂ / x
Solve for x:
- x = 0.033146 mol MgCl₂ × 2 mol AgNO₃ / 1 mol MgCl₂ = 0.006292 mol AgNO₃
4) Molarity AgNO₃
- M = n / V (in liter) = 0.006292 mol / 15 mL × 1000 mL / liter = 0.41947
Round to two significant figures: 0.42 M ← answer
