Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
251–260 of 407 · Easy
Question 251
2 marks · Easy
Answer and see the solution →Calculate the formula for the ionic compound formed when magnesium ions combine with nitrate ions. Show how the charges are balanced in your answer.
Question 252
2 marks · Easy
Answer and see the solution →Ammonium sulfate has the formula (NH4)2SO4. Explain why two ammonium ions are needed in this compound.
Question 253
1 mark · Easy
Answer and see the solution →State the formula for the ionic compound formed when sodium ions combine with bromide ions.
Question 254
3 marks · Easy
Answer and see the solution →The ions formed by magnesium and sulfur combine to make an ionic compound.
(a)[1 mark]State the symbol and charge of the ion formed by magnesium.
(b)[1 mark]State the symbol and charge of the ion formed by sulfur.
(c)[1 mark]Write the formula for the ionic compound formed from these ions.
Question 255
2 marks · Easy
Answer and see the solution →Calculate the correct formula for the ionic compound made from barium ions and hydroxide ions. Show your working.
Question 256
1 mark · Easy
Answer and see the solution →State whether giant ionic compounds have high or low melting points.
Question 257
3 marks · Easy
Answer and see the solution →Magnesium fluoride (MgF_2) is an ionic compound with a giant ionic lattice.
(a)[1 mark]State the type of structure present in magnesium fluoride.
(b)[2 marks]Explain why magnesium fluoride does not conduct electricity when solid.
Question 258
2 marks · Easy
Answer and see the solution →Potassium oxide (K_2O) is an ionic compound formed from K^+ and O^{2-} ions.
Calculate the total positive charge provided by the potassium ions in one formula unit of potassium oxide.
Question 259
2 marks · Easy
Answer and see the solution →Explain why the melting point of sodium oxide (Na_2O) is higher than that of sodium chloride (NaCl).
Question 260
3 marks · Easy
Answer and see the solution →The table shows properties of two substances.
Properties of sodium fluoride and phosphorus trichloride Substance Melting point (°C) Electrical conductivity (solid) Electrical conductivity (liquid) Sodium fluoride (NaF) 998 No Yes Phosphorus trichloride (PCl_3 -112 No No (a)[1 mark]Which substance has a giant ionic structure?
(b)[1 mark]State one piece of evidence from the table that supports your answer in (a).
(c)[1 mark]Explain why sodium fluoride conducts electricity when molten but not when solid.