12.5 g of impure limestone are treated with excess dilute hydrochloric acid. The gas evolved is completely dissolved in a concentrated solution of sodium hydroxide. It was found that the mass of sodium hydroxide solution has increased by 5.1g after absorption.
(a) Write an equation for the reaction between limestone and hydrochloric acid.
(b) Calculate the percentage purity of the limestone.
Reacting masses~~~急
2010-01-04 4:26 am
回答 (1)
2010-01-04 4:54 am
✔ 最佳答案
(a) CaCO3 + 2HCl → CaCl2 + H2O + CO2 (b) From the given, we have CO2 produced = 5.1/44 = 0.116 moles
Hence from the equation of (a), no. of moles of limestone = 0.116 moles, with mass = 0.116 x 100 = 11.6 g
Hence % purity of limestone = 11.6/12.5 x 100% = 92.7%
參考: Myself
收錄日期: 2021-04-13 17:01:17
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