8.1 Two reactions of sulphuric acid are shown in the diagram below. 8.1.1 Define a Lowry-Brønsted base.(2) 8.1.2 Write down a balanced equation for Reaction 1.(3) 8.1.3 Write down the NAME of the salt represented by X.(2) 8.1.4 Write down the FORMULA of ampholyte A.(2) 8.1.5 Write down the formulae of the TWO conjugate acid-base … Read more
The equation for the combustion of butane gas is given below. 7.1 Define the term activation energy.(2) 7.2 Is the combustion reaction of butane exothermic or endothermic? Give areason for the answer.(2) 7.3 Draw a sketch graph of potential energy versus course of reaction for thereaction above. Clearly indicate the following on the graph: Activation … Read more
The simplified diagram below shows a blast furnace used for the extraction of iron from iron ore. P represents a reactant added to the blast furnace. Q and R represent products that leave the blast furnace. Limestone and coke are added to the blast furnace, as shown in the diagram above. Write down the function … Read more
9.1 Oxidation numbers make it easier to determine whether an element or a substance is oxidised or reduced during a chemical reaction. 9.1.1 Define the term oxidation with reference to oxidation numbers. (2) 9.1.3 Calculate the oxidation number of oxygen in H2O2. (1) 9.2 Consider the UNBALANCED equation below: Fe2+(aq) + Câ„“2(g) → Fe3+(aq) + … Read more
When sulphuric acid reacts with water, it ionises in two steps, as shown in the two balanced equations below. 8.1 Define an acid in terms of the Lowry-Brønsted theory. (2) 8.2 Write down the FORMULA of: 8.2.3 A substance that acts as ampholyte in these reactions (1) 8.3 A few drops of bromothymol blue indicator … Read more
1.1.1 How many entrances can you use to access the centre? (2) 1.1.2 You get a call from your friend. The two of you lost each other in thecentre. Your friend is at the Automatic Teller Machine (ATM) atShop No. 40. You are waiting for your friend at Entrance No. 2.Explain to your friend the … Read more
Electronegativity of atoms may be used to explain the polarity of bonds. 2.1 Define the term electronegativity. (2) 2.2 Draw the Lewis diagram of an oxygen difluoride molecule. (2) 2.3 Calculate the electronegativity difference between O and F in oxygendifluoride and predict the polarity of the bond. (2) 2.4 A polar bond does not always … Read more