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
231–240 of 423 · Normal
Question 231
6 marks · Normal
Answer and see the solution →Potassium carbonate ( ) reacts with dilute hydrochloric acid:
(a)[2 marks]A student adds 0.20 g of solid potassium carbonate to 25.0 cma3 of dilute hydrochloric acid (an excess is present). Calculate the number of moles of potassium carbonate used. (Ar: K = 39, C = 12, O = 16)
(b)[2 marks]Calculate the maximum volume (in cma3) of carbon dioxide gas produced at room temperature and pressure. (Molar volume = 24,000 cma3 at rtp.)
(c)[2 marks]After the reaction, the solution is made up to 100.0 cma3 in a volumetric flask. Calculate the concentration, in mol/dma3, of potassium chloride present in the final solution.
Question 232
6 marks · Normal
Answer and see the solution →Citric acid reacts with sodium bicarbonate according to the following equation:
(a)[2 marks]A student reacts 0.420 g of sodium bicarbonate () with excess citric acid. Calculate the number of moles of sodium bicarbonate used. (Ar: Na = 23, H = 1, C = 12, O = 16)
(b)[2 marks]Calculate the volume, in dma3, of carbon dioxide gas produced at room temperature and pressure. (Molar volume = 24 dma3 at rtp.)
(c)[2 marks]The carbon dioxide produced is collected and completely dissolved in 250 cma3 of distilled water. Calculate the concentration of carbon dioxide (in mol/dma3) in this solution.
Question 233
6 marks · Normal
Answer and see the solution →A student reacts excess magnesium ribbon with 100 cm³ of 2.0 mol/dm³ hydrochloric acid in a flask at room temperature and pressure (rtp). Magnesium reacts with hydrochloric acid as follows:
(a)[2 marks]Calculate the amount, in moles, of hydrochloric acid present in 100 cm³ of 2.0 mol/dm³ HCl.
(b)[3 marks]Calculate the maximum volume, in cm³, of hydrogen gas produced at rtp.
(c)[1 mark]Suggest one reason why the actual volume of hydrogen collected might be less than this calculated value.
Question 234
6 marks · Normal
Answer and see the solution →A chemistry class investigates the reaction between solid calcium carbonate and dilute sulfuric acid. The reaction is:
(a)[2 marks]Explain why, after a short time, the reaction between calcium carbonate and dilute sulfuric acid slows down, even though there is still acid present.
(b)[2 marks]A student wants to calculate the concentration (in mol/dm³) of sulfuric acid if 5.0 g of CaCO3 is completely reacted using 250 cm³ of acid. (Ar: Ca = 40, C = 12, O = 16)
(c)[2 marks]The same student collects the carbon dioxide produced. Explain how they can use the volume of CO₂ collected at rtp to check if the reaction went to completion.
Question 235
2 marks · Normal
Answer and see the solution →State the charge that a magnesium ion and an oxide ion have in magnesium oxide. Give both ion symbols.
Question 236
4 marks · Normal
Answer and see the solution →This question is about magnesium oxide.
(a)[3 marks]Draw a dot-and-cross diagram to show the ionic bonding in magnesium oxide (MgO). Clearly show all the electrons, their arrangement, and the charges on the ions.
(b)[1 mark]Why are both ions in MgO drawn with full outer shells?
Question 237
3 marks · Normal
Answer and see the solution →Explain, using charges, why strong electrostatic attraction exists between the ions in magnesium oxide (MgO), and calculate the charge difference between a Mg^{2+} ion and an O^{2-} ion.
Question 238
3 marks · Normal
Answer and see the solution →Explain how magnesium and oxygen atoms form ions when magnesium reacts with oxygen. Include reference to electrons and charges.
Question 239
4 marks · Normal
Answer and see the solution →The table below shows the number of electrons in the outer shell for atoms and the resulting ions in magnesium oxide.
Particle Electrons in Outer Shell Mg atom 2 Mg ion 8 O atom 6 O ion 8 (a)[2 marks]Using the data, explain how the outer shell electron configuration changes for magnesium and oxygen when MgO forms.
(b)[2 marks]How does this information support the use of dot-and-cross diagrams in representing magnesium oxide?
Question 240
1 mark · Normal
Answer and check →What is the main reason magnesium oxide is held together as an ionic compound?
- A.Electrons are shared between the Mg and O atoms.
- B.Positive and negative ions are strongly attracted by electrostatic forces.
- C.Both ions have full outer shells.
- D.Magnesium and oxygen atoms form covalent bonds.