Neco Model Questions Vol1 2020 Chemistry Question 2

Practice practical question 2 from the 2020 Neco Model Questions Vol1 Chemistry examination. This question covers Periodic Table .

Neco Model Questions Vol1 2020 Chemistry Practical
Topic: Periodic Table
Question 2 NECO_MODEL_QUESTIONS_VOL1 • 2020 • CHEMISTRY • practical

A student carries out a gravimetric analysis to determine the percentage composition of copper in a sample of an unknown copper(II) oxide.

Question Parts

( a )
Write the balanced chemical equation for the formation of copper(II) oxide when copper metal is heated in air.
( b )
Using the data below, calculate (i) the mass of CuO obtained after heating, (ii) the mass of copper present in the CuO, and (iii) the percentage by mass of copper in the oxide. Data: mass of empty crucible = 45.12 g; mass of crucible + CuO after heating = 45.78 g.
( c )
From the percentage obtained, identify the unknown oxide by comparing with the theoretical percentages given below: CuO – 79.9 %; Fe₂O₃ – 69.9 %; ZnO – 80.6 %; Al₂O₃ – 53.1 %.
( d )
Discuss two possible sources of error in this gravimetric determination and explain how each could affect the calculated percentage of copper.

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About This Question

This is Neco Model Questions Vol1 2020 Chemistry Question 2. It is one of the practical questions from the 2020 Neco Model Questions Vol1 Chemistry examination.

The question covers Periodic Table .

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