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Aluminium alloys are used instead of pure aluminium in aircraft manufacture - Edexcel - GCSE Chemistry - Question 4 - 2021 - Paper 1
Question 4
Aluminium alloys are used instead of pure aluminium in aircraft manufacture. (a) Explain, in terms of the arrangement of metal particles, why aluminium alloys are s... show full transcript
Worked Solution & Example Answer:Aluminium alloys are used instead of pure aluminium in aircraft manufacture - Edexcel - GCSE Chemistry - Question 4 - 2021 - Paper 1
Step 1
Explain, in terms of the arrangement of metal particles, why aluminium alloys are stronger than pure aluminium.
Answer
Aluminium alloys are stronger than pure aluminium primarily due to the different sizes of atoms in the alloy. In pure aluminium, all the metal particles are uniform in size, which allows them to slide past each other easily. However, in an alloy, the presence of different-sized atoms disrupts this uniformity and inhibits the movement of these particles. This results in enhanced strength because the varied sizes create more obstacles for dislocation movement, making it more difficult for the particles to slide over one another. Therefore, the layered arrangement of differently sized atoms in alloys contributes to improved strength compared to the uniform arrangement in pure aluminium.
Step 2
A 695.0 g sample of an aluminium-magnesium alloy contains 2.00% by mass of magnesium. Calculate the mass of aluminium in this sample.
Answer
To find the mass of aluminium, we first need to determine the mass of magnesium in the alloy. We can calculate the mass of magnesium using the percentage given:
ext{Mass of magnesium} = rac{2.00}{100} imes 695.0 ext{ g} = 13.9 ext{ g}
Next, we subtract the mass of magnesium from the total mass of the alloy to find the mass of aluminium:
ext{Mass of aluminium} = 695.0 ext{ g} - 13.9 ext{ g} = 681.1 ext{ g}
Step 3
Figure 5 shows a graph of the relative strength of aluminium-magnesium alloys when the percentage by mass of magnesium in the alloy is changed.
Answer
In the graph, we would typically expect to see a trend illustrating that as the percentage of magnesium in the alloy increases, the strength of the aluminium-magnesium alloy also tends to increase up to a certain point and then may plateau or decline. The relationship can vary, so analyzing the specific graph would provide more detailed insights.