Chemistry questions

Chemistry questions to help you revise.
For the answer hover your mouse over the word ‘Answer’

No Question Answer
1 What process would you use to separate some blue dye from black ink (distillation, filtrtaion, evaporation or chromatography)?  [tooltips keyword=”Answer”  content=Chromatography]
2 What colour does copper turn when it is heated?  [tooltips keyword=”Answer”  content=”Black (copper forms copper oxide when heated)”]
3 Flour is insoluble in water. When flour is shaken with water it will form a A: solution B: suspension C: filtrate  [tooltips keyword=”Answer”  content=suspension]
4 Iron, Copper, Aluminium, Plastic. Which of these substances is used to make electric wiring.. Explain the reasons.  [tooltips keyword=”Answer” content=”Copper because it is a good conductor of electricity and is also ductile (can be pulled into wires)”]
5 If some salt is dissolved in warm water the water used is called the A: solution, B: solute, C: solvent? [tooltips keyword=”Answer” content=”Water is the solvent“]
6 What process of separation would you use to obtain salt from salty water (filtration, distillation or evaporation)?  [tooltips keyword=”Answer” content=”Evaporation (the solution is warmed and the water evaporates, leaving the salt)”]
7 Iron, Copper, Aluminium, Plastic. Which of these substances is used to make the body of an aircraft.. Explain the reasons.  [tooltips keyword=”Answer” content=”Aluminium because it is light (has a low density)”]
8 What process of separation would you use to remove sand from salty water (filtration, distillation or evaporation)?  [tooltips keyword=”Answer” content=Filtration]
9 A large lump of salt is dropped into cold water. Describe three things you could do to make the salt dissolve quicker  [tooltips keyword=”Answer” content=”1. Grind the salt up into smaller lumps.
2. Use warm water.
3. Stir the mixture”]
10 Name a gas that relights a glowing splint  [tooltips keyword=”Answer” content=Oxygen]
11 Name a dense, yellow metal that is often used to make jewellery.  [tooltips keyword=”Answer” content=Gold]
12 Name any two substances found in the home that may be alkaline:   [tooltips keyword=”Answer” content=”Oven cleaner (caustic soda: sodium hydroxide), Indigestion powder (Milk of magnesia: magnesium hydroxide), Washing soda (sodium carbonate), Garden lime” ]
13 Name an element that burns with a bright white flame   [tooltips keyword=”Answer” content=”Magnesium ribbon”]
14 Iron, Copper, Aluminium, Plastic. Which of these substances would you use to make a washing up bowl.. give a reason.   [tooltips keyword=”Answer” content=”Plastic because plastic is cheap, light and easily moulded”]
15 What colour is magnesium oxide   [tooltips keyword=”Answer” content=White]
16 What colour is sulphur?  [tooltips keyword=”Answer” content=Yellow]
17 Iron, Copper, Aluminium, Plastic. Which of these substances is usually used to make bridges. Explain the reasons.   [tooltips keyword=”Answer” content=”Iron because it is strong and relatively cheap”]
18 Explain some disadvantages of using iron to make bridges  [tooltips keyword=”Answer” content=”Iron is heavy and can go rusty”]
19 If some salt is dissolved in warm water the resulting mixture will be called a …… A: solution, B: solute, C: solvent ?  [tooltips keyword=”Answer” content=Answer A: Solution]
20 Plastic is often used to make cheap objects like washing up bowls.. give two disadvantages of using plastic.  [tooltips keyword=”Answer” content=”Plastic is not very strong and can melt easily”]
21 Is sulphur a mixture, compound or element  [tooltips keyword=”Answer” content=”Sulphur is an element”]
22 If Litmus indicator was added to a liquid of pH 5 what colour would it go?  [tooltips keyword=”Answer” content=”Yellow, because pH 5 is a weak acid]
23 If some salt is dissolved in warm water the salt is called the A: solution, B: solute, C: solvent ?  [tooltips keyword=”Answer” content=Answer B: Solute]
24 What colour would universal indicator turn when added to indigestion powder?  [tooltips keyword=”Answer” content=”Blue. This is because indigestion powder contains a mild alkali”]
25 Sugar is soluble in water. If sugar is shaken with water it will form a A: solution, B: suspension C: filtrate   [tooltips keyword=”Answer” content=”Answer A: Solution”]
26 What chemical is formed when copper is heated in air?  [tooltips keyword=”Answer” content=”Copper oxide. (the copper reacts with oxygen from the air)”]
27 What process of separation would you use to obtain fresh water from salty water (filtration, distillation or evaporation)?  [tooltips keyword=”Answer” content=”Distillation”]
28 What colour is hydrated copper sulphate  [tooltips keyword=”Answer” content=Blue]
29 Describe two things that happen when water is added to anhydrous copper sulphate  [tooltips keyword=”Answer” content=”1. The anhydrous copper sulphate would change colour (from white to blue) and 2. It would get warm”]
30 Why does iron go brown when it touches copper sulphate solution?  [tooltips keyword=”Answer” content=”Iron is more reactive than copper so displaces copper from the copper sulphate. The copper makes the iron look brown.”]
31 Name an element that burns to form an acidic oxide  [tooltips keyword=”Answer” content=”Sulphur. Most non-metals burn to form an acid”]
32 What substance is used during the test for carbon dioxide gas   [tooltips keyword=”Answer” content=”Bubble it through limewater which will go cloudy”]
33 To show if a liquid contains water you would add it to what chemical?   [tooltips keyword=”Answer” content=”Add water to anhydrous copper  sulphate (or anhydrous cobalt chloride) which will change colour”]
34 What colour does anhydrous cobalt chloride turn when added to water?  [tooltips keyword=”Answer” content=”from blue to pink”]
35 approximately how many elements are there? a) less than 50. b) between 50 and 150 c) more than 150   [tooltips keyword=”Answer” content=”Answer B: There are about 100 elements.”]
36 Pick out an alkaline oxide from the list below: A: sulphur dioxide, B: sodium chloride, C: magnesium oxide  [tooltips keyword=”Answer” content=”Answer C: Magnesium oxide”]
37 Name the liquid formed formed when blue copper sulphate decomposes:   [tooltips keyword=”Answer” content=Water]
38 Why is lime sometimes added to garden soil?  [tooltips keyword=”Answer” content=”To neutralise the acid (lime is an alkali”]
39 How could you show if a colourless liquid contained anything dissolved in it?  [tooltips keyword=”Answer” content=”Let the water evaporate. Anything dissolved would appear as a residue”]
40 Pick a neutral oxide from this list: Magnesium oxide, water, sulphur dioxide, carbon dioxide
  [tooltips keyword=”Answer” content=Water]
41 What is the chemical test for oxygen?   [tooltips keyword=”Answer” content=”See if it re-lights a glowing splint”]
42 In a common industrial process, carbon is heated with iron oxide. What everyday substance is being produced?  [tooltips keyword=”Answer” content=Iron]
43 Iron is more reactive than copper. Describe two changes you may observe if iron is added to copper sulphate solution.   [tooltips keyword=”Answer” content=”The copper sulphate solution would lose its colour and the iron would get coated with pink copper”]
44 Is water a mixture, compound or element?   [tooltips keyword=”Answer” content=Compound]
45 If copper sulphate were heated would it’s mass gain, get less or not change?  [tooltips keyword=”Answer” content=”Lose mass. This is because it gives off water vapour”]
46 Name a substance with a pH value less than pH7  [tooltips keyword=”Answer” content=”Lemon juice (or any acid”]
47 Is air a mixture, compound or element?  [tooltips keyword=”Answer” content=”Air is a mixture”]
48 Carbon is more reactive than copper. What two chemicals would be formed when powdered wood charcoal is heated with copper oxide?
  [tooltips keyword=”Answer” content=”Carbon dioxide and copper”]
49 Write the word equation for the reaction between magnesium and copper oxide
  [tooltips keyword=”Answer” content=”magnesium and copper oxide → magnesium oxide and copper”]
50 Which of these elements conducts electricity?
Sulphur, carbon, iodine, oxygen
   [tooltips keyword=”Answer” content=Carbon]
51 Is carbon a metal or non-metal ?  [tooltips keyword=”Answer” content=Non-metal]
52 Name a chemical compound that decomposes to produce carbon dioxide when it is heated:  [tooltips keyword=”Answer” content=”copper carbonate or calcium carbonate (there are others but I am not listing them all!”]
53 If some copper foil were heated strongly in air would it’s mass increase, decrease or not change?  [tooltips keyword=”Answer” content=”Increase because the copper combines with oxygen from the air”]
54 If anhydrous copper sulphate is mixed with cold water , the resulting mixture is slightly warm. Why do you think this is?  [tooltips keyword=”Answer” content=”Because a chemical reaction takes place”]
55 Name a gas that causes acid rain  [tooltips keyword=”Answer” content=”Sulphur dioxide (or carbon dioxide)”]
56 A piece of copper is placed into a test tube which is sealed and then weighed. The copper is heated until it goes black. The same sealed test tube + copper is now weighed again. Would the mass increase, decrease or not change?  [tooltips keyword=”Answer” content=”The mass would not change”]
57 Write down the word equation for the reaction that takes place when magnesium burns  [tooltips keyword=”Answer” content=”Magnesium + oxygen → magnesium oxide”]
58 Name a non-metallic element that conducts electricity   [tooltips keyword=”Answer” content=Carbon]
59 Name a non-metallic element that melts easily and burns with a blue flame to form a gas with a choking smell.   [tooltips keyword=”Answer” content=Sulphur]
60 Name a substance that will burn completely away when heated, forming a colourless gas that turns limewater cloudy.   [tooltips keyword=”Answer” content=Carbon]
61 Name a metallic element that burns in air to form an alkaline oxide   [tooltips keyword=”Answer” content=Magnesium]
62 Why is lime sometimes added to garden soil?   [tooltips keyword=”Answer” content=”To neutralize an acid soil”]
63 A substance has a melting point of 113°C and a boiling point of 445°C. Is it a solid liquid or gas?    [tooltips keyword=”Answer” content=Solid]
64 What is the test for oxygen gas?   [tooltips keyword=”Answer” content=”Re-lights a glowing splint”]
65 What colour does anhydrous cobalt chloride turn when added to water?    [tooltips keyword=”Answer” content=”From blue to pink”]
66 Describe two things that happen when water is added to anhydrous copper sulphate    [tooltips keyword=”Answer” content=”1. Changes colour (from white to blue)”]
67 Which element has the symbol Mg?
   [tooltips keyword=”Answer” content=Magnesium]
68 Give the name of a natural substance made mostly of calcium carbonate.   [tooltips keyword=”Answer” content=”Chalk or limestone (or bones)”]
69 What is the normal percentage of oxygen in the air?    [tooltips keyword=”Answer” content=21%]
70 Name the most abundant gas in the atmosphere    [tooltips keyword=”Answer” content=Nitrogen]
71 A substance has a melting point of -39°C and a boiling point of 357°C. Is it a solid liquid or gas?    [tooltips keyword=”Answer” content=Liquid]
72 What percentage of the air is nitrogen?
   [tooltips keyword=”Answer” content=79%]
73 Name two products when magnesium reacts with zinc oxide:    [tooltips keyword=”Answer” content=”Magnesium oxide and zinc”]
74 Name TWO substances released into the air when a candle burns.    [tooltips keyword=”Answer” content=”Carbon dioxide and water”]
75 Give the name and colour of the products formed when burning magnesium reacts with carbon dioxide.    [tooltips keyword=”Answer” content=”Magnesium oxide and carbon”]
76 Some copper foil is heated in a sealed tube until the copper stops changing colour. What gas remains in the tube?   [tooltips keyword=”Answer” content=”Mostly nitrogen”]
77 Suggest a pH value for some indigestion powder designed to cure acid indigestion.   [tooltips keyword=”Answer” content=”pH 10 (anything more than pH 7 and less than pH12″]
78 What gas is formed when sulphur burns?    [tooltips keyword=”Answer” content=”Sulphur dioxide”]
79 What gaseous product would you expect when carbon reacts with magnesium oxide?   [tooltips keyword=”Answer” content=”Carbon dioxide”]
80 Aluminium is a common metal… what makes it so expensive to manufacture?   [tooltips keyword=”Answer” content=”Aluminium uses lots of electricity to manufacture it.”]
81 If copper metal were heated would it’s mass gain, get less or not change?   [tooltips keyword=”Answer” content=”Copper metal will gain mass when heated in air”]
82 What is the chemical name for the substance we call table salt?    [tooltips keyword=”Answer” content=”Sodium chloride”]
83 What do we call the reaction between sodium hydroxide and hydrochloric acid.
   [tooltips keyword=”Answer” content=Neutralization]
84 What is the approximate percentage of oxygen in the atmosphere  [tooltips keyword=”Answer” content=21%]
85 What would happen to a piece of copper if it were heated in a tube of nitrogen?   [tooltips keyword=”Answer” content=”Nothing would happen”]
86 Name one of the two products formed when sodium hydroxide reacts with hydrochloric acid hydrochloric acid.  [tooltips keyword=”Answer” content=”Salt (sodium chloride) or water”]
87 What common name is given to the chemical called sodium chloride?  [tooltips keyword=”Answer” content=”Table salt”]
88 Name a gas that turns limewater cloudy  [tooltips keyword=”Answer” content=”Carbon dioxide”]
89 What is the chemical test for oxygen gas ?  [tooltips keyword=”Answer” content=”Re-lights a glowing splint”]
90 What is the chemical symbol for oxygen?
  [tooltips keyword=”Answer” content=O]
91 What experiment would you do to try and convince a friend that copper sulphate is a compound?   [tooltips keyword=”Answer” content=”Heat it and show that it decomposes into two substances (water and a white powder called anhydrous copper sulphate.”]
92 A substance has a melting point of -218°C and a boiling point of -183°C. Is it a solid liquid or gas?  [tooltips keyword=”Answer” content=Gas]
93 Aluminum is often used to make saucepans. Describe properties of aluminium that make it suitable for this.   [tooltips keyword=”Answer” content=”Aluminium is light and doesnt burn easily”]
94 Name a gas that burns with a squeak [tooltips keyword=”Answer”]]  zy pop   [tooltips keyword=”Answer” content=Hydrogen]