Pearson Edexcel IGCSE · Science (Double Award)

Principles of chemistry: Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on Principles of chemistry.

10 questions27 marksFree, no account

Question 1

1 mark

Which process involves a substance losing energy and its particles moving closer together to form a regular, fixed arrangement?

Question 2

1 mark

What is the relative formula mass (\(M_r\)) of ammonium sulfate, \((NH_4)_2SO_4\)?
(\(A_r\) values: \(N = 14\), \(H = 1\), \(S = 32\), \(O = 16\))

Question 3

1 mark

Why does diamond have a significantly higher melting point than \(C_{60}\) fullerene, even though both are made of carbon atoms?

Question 4

1 mark

An atom of sodium has an atomic number of \(11\) and a mass number of \(23\). What is the total number of neutrons in the nucleus of this atom?

Question 5

1 mark

Which statement correctly explains why sodium chloride conducts electricity when molten but not when in the solid state?

Question 6

2 marks

Determine the number of protons and the number of electrons present in a sodium ion, \(Na^{+}\). (The atomic number of sodium is \(11\) and its mass number is \(23\)).

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Question 7

4 marks

A sample of a copper oxide is reduced to its elements, producing \(1.27\text{ g}\) of copper and \(0.16\text{ g}\) of oxygen. Calculate the empirical formula of this copper oxide. (\(A_r\) values: \(Cu = 63.5, O = 16\))

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Question 8

6 marks

An organic compound is found to contain \(80\%\) carbon and \(20\%\) hydrogen by mass. Given that its relative formula mass (\(M_r\)) is \(30\), determine the molecular formula of the compound. (\(A_r\) values: \(C = 12, H = 1\))

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Question 9

5 marks

(a) Describe the arrangement and movement of particles in a liquid.
(b) State the name of the change of state when a liquid becomes a solid.
(c) Ammonia gas (\(NH_3\)) and hydrogen chloride gas (\(HCl\)) are released at opposite ends of a glass tube. They diffuse and react to form a white ring of ammonium chloride (\(NH_4Cl\)). Explain why the ring forms closer to the \(HCl\) end of the tube. (\(M_r\) of \(NH_3 = 17\), \(M_r\) of \(HCl = 36.5\))

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Question 10

5 marks

An oxide of copper is analyzed and found to contain 12.7 g of copper and 1.6 g of oxygen.
(a) Determine the empirical formula of this oxide of copper.
(b) Write a balanced symbol equation for the reaction of copper with oxygen to form this specific oxide. Include state symbols.
(\(A_r\) values: \(Cu = 63.5\), \(O = 16\))

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