Question
This question is about metals.
(a) State three general physical properties common to most metals.[3]
1
2
3
(b) Metals are often used in the form of alloys.
(i) State the meaning of the term alloy.[1]
(ii) Explain in terms of their properties why alloys are used instead of pure metals.[1]
(iii) Stainless steel is an alloy.
Give one use of stainless steel.[1]
(c) Place these metals in order of their reactivity with oxygen.
copper
magnesium
potassium
zinc
Put the least reactive metal first.[2]
(d) When 4.8g of magnesium reacts with excess oxygen, 8.0g of magnesium oxide is formed.
Calculate the minimum mass of magnesium needed to produce 24.0g of magnesium oxide.
minimum mass = g [1] [Total: 9]
Answer/Explanation
Ans:
a) 1 mark each for any three of:
-
- conduct electricity / conduct heat
- malleable
- ductile
- shiny / lustrous
- sonorous / rings when hit
(b)(i) mixture of metal with another element
(b)(ii) (alloy is) hard(er) / (more) resistant to corrosion / strong(er)
(b)(iii) cutlery / chemical plant / surgical equipment
(c) copper , zinc , magnesium , potassium (2)
if 2 marks not scored: 1 mark for one consecutive pair reversed
(d) 14.4 (g)
Question
The table shows some properties of four halogens.
(a) (i) Complete the table by predicting:
● the boiling point of chlorine
● the density of fluorine at its melting point.
(ii) Describe the trend in the melting points of the halogens down the group.
(iii) Deduce the physical state of iodine at 130°C.
Explain your answer.
(b) (i) Give the electronic structure of a fluorine atom.
(ii) Explain why a fluoride ion has a single negative charge.
(c) Magnesium reacts with excess fluorine to produce magnesium fluoride.
When 2.40g of magnesium is reacted, 6.20g of magnesium fluoride is produced. Calculate the mass of magnesium needed to produce 1.24g of magnesium fluoride.
mass of magnesium = ………………………… g
Answer/Explanation
Answer:
(a) (i) boiling point of chlorine: any values between –100 and 10 (°C) (inclusive of these values) (1)
density of fluorine: any values between 0.20 and 1.55 (g / cm3) (inclusive of these values) (1)
(ii) increases
(iii) liquid (1)
130 (°C) is between the melting and boiling point / the melting point is lower than 130 (°C) AND the boiling point is above
130 (°C) (1)
(b) (i) 2.7
(ii) the number of electrons is one more than the number of protons / it has 9 protons and 10 electrons (1)
(c) 0.48(0) (g)
Question
Iron is extracted by heating a mixture of coke (carbon), limestone and iron ore in air in a blast furnace.
A diagram of the blast furnace is shown.
(a) Name the ore of iron added to the blast furnace.
(b) The impurities in the iron ore are removed as slag.
(i) What information in the diagram shows that slag is less dense than molten iron?
(ii) Which one of the substances added to the blast furnace helps to remove the impurities?
Explain how it does this.
substance ……………………………………………………………………………………………………………
explanation ………………………………………………………………………………………………………….
(c) Hot air is blown into the blast furnace.
Explain why.
(d) The chemical equation for one of the reactions in the blast furnace is shown.
\(Fe_2O_3 + 3CO → 2Fe + 3CO_2\)
(i) How does this equation show that \(Fe_2O_3\) has been reduced?
(ii) When 16.0g of \(Fe_2O_3\) react with excess carbon monoxide, 11.2g of iron are produced.
Calculate the mass of iron produced when 4.0g of \(Fe_2O_3\) reactwith excess carbon monoxide.
mass of iron = ………………………… g
(e) An isotope of iron is shown.
\(^{58}_{26} Fe\)
Deduce the number of electrons, protons and neutrons in an atom of this isotope of iron.
number of electrons Ans…………………………………………………………………………………………………….
number of protons ………………………………………………………………………………………………………
number of neutrons …………………………………………………………………………………………………….
(f) Iron is a transition element.
Which two of these statements about iron are correct?
Tick two boxes.
Answer/Explanation
Answer:
(a) hematite
(b) (i) slag floats on iron / slag is above the iron ORA
(ii)
limestone (1)
AND 1 mark each for any 2 of:
• it decomposes / it breaks down
• forms calcium oxide / forms CaO
• reacts with impurities / reacts with silicon dioxide / reacts with silicates / reacts with silica / reacts with \(SiO_2\)
(c) to form carbon monoxide / to burn the coke / to burn the carbon
(d) (i) oxygen removed from \(Fe_2O_3\) / iron oxide loses oxygen
(ii) 2.8 (g)
(e) electrons: 26 (1)
protons: 26 (1)
neutrons: 32 (1)
(f) first box down ticked (iron forms coloured compounds) (1)
second box down ticked (iron can act as a catalyst) (1)