10.1. Water
A subsection of Chemistry, 0620, through 10. Chemistry of the environment
Listing 10 of 242 questions
Impure water needs to be treated if it is to be used in the home. Explain why fi ltration and chlorination are used in the water treatment process. State one use of water in the home. Describe a chemical test for water. test result Complete the diagram below to show the electron arrangement in a water molecule. O H H Is the bonding in water covalent or ionic? Give a reason for your answer. Pure water is neutral. Which one of these pH values is neutral? Put a ring around the correct answer. pH 0 pH 6 pH 7 pH 9 pH 13 Water reacts with sodium. The products are sodium hydroxide and hydrogen. Write a word equation for this reaction.
0620_s13_qp_23
THEORY
2013
Paper 2, Variant 3
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Sodium sulfate is a solid with a high melting point. Sodium sulfate conducts electricity when molten but not when solid. What type of structure is sodium sulfate? Tick one box. structure of separated atoms simple molecular structure giant ionic structure giant covalent structure Describe a test for sulfate ions. test result Describe how simple distillation is used to separate water from an aqueous solution of sodium sulfate. In your answer, refer to: ● the apparatus used, ● changes in state, ● differences in boiling points. You may use a diagram. What would you observe when a piece of blue cobalt chloride paper is dipped into water? Describe how impure water is treated so that it can be used for drinking.
0620_s14_qp_23
THEORY
2014
Paper 2, Variant 3
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This question is about cobalt and compounds of cobalt. Describe how you could prepare a pure sample of crystals of hydrated cobalt(sulfate using dilute sulfuricacid and an excess of cobalt(carbonate. Complete the table to calculate the relative formula mass of anhydrous cobalt(sulfate, CoSO4. Use your Periodic Table to help you. type of atom number of atoms relative atomic mass cobalt sulfur 1 × 32 = 32 oxygen  relative formula mass =  Complete the table to show the number of electrons, protons and neutrons in the oxygen atom and cobalt ion shown. number of electrons number of neutrons number of protons 17O 59Co2+  Anhydrous cobalt(chloride is used to test for water. State the colour change when water is added to anhydrous cobalt(chloride. from to  An alloy of cobalt, chromium and molybdenum is used to make cutlery. Which one of the following diagrams best represents the structure of the alloy? Draw a circle around the correct answer. A B C D  Which one of these substances is also used to make cutlery? Tick one box. mercury sodium stainless steel graphite  
0620_s19_qp_32
THEORY
2019
Paper 3, Variant 2
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Questions Discovered
242