calculate the mass of sodium hydroxide?
2020-05-19 9:33 pm
5. Calculate the mass of sodium hydroxide that must be added to 1.80 liters of 0.210M magnesium chloride to precipitate all the magnesium ions in the form of magnesium hydroxide.
回答 (1)
2020-05-19 10:06 pm
Molar mass of NaOH = (23.0 + 16.0 + 1.0) g/mol = 40.0 g/mol
2NaOH(aq) + MgCl₂(aq) → Mg(OH)₂(s) + 2NaCl
Mole ratio NaOH : MgCl₂ = 2 : 1
Moles of MgCl₂ = (0.210 mol/L) × (1.80 L) = 0.378 mol
Moles of NaOH = (0.378 mol) × 2 = 0.756 mol
Mass of NaOH = (0.756 mol) × (40.0 g/mol) = 30.2 g
====
OR:
(0.210 mol MgCl₂/L) × (1.80 L) × (2 mol NaOH / 1 mol MgCl₂) × (40.0 g NaOH / 1 mol NaOH)
= 30.2 g NaOH
2NaOH(aq) + MgCl₂(aq) → Mg(OH)₂(s) + 2NaCl
Mole ratio NaOH : MgCl₂ = 2 : 1
Moles of MgCl₂ = (0.210 mol/L) × (1.80 L) = 0.378 mol
Moles of NaOH = (0.378 mol) × 2 = 0.756 mol
Mass of NaOH = (0.756 mol) × (40.0 g/mol) = 30.2 g
====
OR:
(0.210 mol MgCl₂/L) × (1.80 L) × (2 mol NaOH / 1 mol MgCl₂) × (40.0 g NaOH / 1 mol NaOH)
= 30.2 g NaOH
收錄日期: 2021-05-01 22:38:31
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20200519133351AAG5BAY