This question is about properties of materials - Edexcel - GCSE Chemistry Combined Science - Question 7 - 2016 - Paper 1
Question 7
This question is about properties of materials.
(a) Figure 6 shows some properties of steel and Kevlar®.
(b) The use of nanoparticles has increased in recent years.... show full transcript
Worked Solution & Example Answer:This question is about properties of materials - Edexcel - GCSE Chemistry Combined Science - Question 7 - 2016 - Paper 1
Step 1
Calculate the surface area to volume ratio of this cube of silver.
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Answer
To find the surface area (SA) and volume (V) of the cube:
Calculate the Surface Area:
The formula for the surface area of a cube is:
SA=6a2
where a is the length of one side. Since a=2extcm:
SA=6(2extcm)2=6imes4extcm2=24extcm2
Calculate the Volume:
The formula for the volume of a cube is:
V=a3
Thus,
V=(2extcm)3=8extcm3
Calculate the Surface Area to Volume Ratio:
The surface area to volume ratio is calculated as:
Suggest an explanation of why a given mass of silver is more effective as a catalyst when used as nanoparticles rather than in a powder form.
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Nanoparticles of silver have a significantly larger surface area compared to the volume they occupy than in powder form. This increased surface area allows for more active sites for reactions to occur. Therefore, a given mass of silver in nanoparticle form can effectively interact with reactants more frequently, leading to a higher rate of reaction. Additionally, nanoparticles can often penetrate into the reaction environment more effectively than larger powder particles, contributing to improved catalytic activity.