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
421–423 of 423 · Normal
Question 421
8 marks · Normal
Answer and see the solution →This question is about calculating relative formula masses (Mr) and converting between cm³ and dm³.
(a)[3 marks]Sodium carbonate decahydrate, Na2CO3·10H2O, is used in cleaning products. Calculate the relative formula mass (Mr) of sodium carbonate decahydrate. (Ar: Na = 23, C = 12, O = 16, H = 1)
(b)[3 marks]A student dissolves 5.7 g of sodium carbonate decahydrate in enough water to make 250 cm³ of solution. Calculate the concentration of the solution in g/dm³.
(c)[2 marks]Convert 250 cm³ to dm³. Show your working.
Question 422
8 marks · Normal
Answer and see the solution →This question is about using moles and gas molar volumes in calculations. Ammonium chloride decomposes on heating according to the following equation: NH4Cl(s) NH3(g) + HCl(g)
(a)[2 marks]Define the mole in terms of the number of particles.
(b)[2 marks]Recall the volume occupied by 1 mole of any gas at rtp in: (i) dm³ (ii) cm³
(c)[4 marks]Calculate the total volume of gas (in cm³) produced at rtp when 5.35 g of ammonium chloride decomposes completely. (Ar: N = 14, H = 1, Cl = 35.5; molar volume = 24,000 cm³ mol⁻¹)
Question 423
8 marks · Normal
Answer and see the solution →A student reacts sodium carbonate with hydrochloric acid and collects the carbon dioxide gas produced.
(a)[2 marks]Write a balanced chemical equation (including state symbols) for the reaction between sodium carbonate and hydrochloric acid.
(b)[2 marks]The student adds 0.0500 mol of sodium carbonate to 100 cm³ of 1.00 mol/dm³ hydrochloric acid. Calculate the number of moles of HCl present.
(c)[2 marks]Explain which reactant is in excess, using calculations.
(d)[2 marks]Calculate the volume (in dm³) of CO₂ produced at rtp. (Molar volume at rtp = 24 dm³ mol⁻¹)