Neco 2019 Chemistry Question 45

Practice objective / multiple choice question 45 from the 2019 Neco Chemistry examination.

Neco 2019 Chemistry Objective / Multiple Choice Medium Difficulty
Question 45 NECO • 2019 • CHEMISTRY • objective

A 5.00 g sample of a mixture of calcium carbonate (CaCO_{3}) and sodium chloride is heated strongly. The CO_{2} gas evolved is collected over water at 25\(^\circ\)C and a total pressure of 760 mmHg. The gas syringe reading is 0.500 L. The water vapour pressure at 25\(^\circ\)C is 23.8 mmHg. (a) Determine the mass of CaCO_{3} present in the mixture. (b) Calculate the theoretical mass of CaO that should be formed. (c) If the actual mass of CaO obtained after cooling is 0.95 g, calculate the percent yield.

Answer Options

A. Mass CaCO_{3}=2.10 g; theoretical CaO mass=1.18 g; percent yield=80.5 %
B. Mass CaCO_{3}=1.85 g; theoretical CaO mass=1.04 g; percent yield=91.3 %
Correct Answer C. Mass CaCO_{3}=1.98 g; theoretical CaO mass=1.11 g; percent yield=85.7 %
D. Mass CaCO_{3}=2.00 g; theoretical CaO mass=1.12 g; percent yield=84.8 %
Correct Answer
C
Correct Option:
Mass CaCO_{3}=1.98 g; theoretical CaO mass=1.11 g; percent yield=85.7 %

About This Question

This is Neco 2019 Chemistry Question 45. It is one of the objective questions from the 2019 Neco Chemistry examination.

Difficulty level: Medium .

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