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Magnesium oxide nanoparticles can kill bacteria - AQA - GCSE Chemistry - Question 6 - 2014 - Paper 1
Question 6
Magnesium oxide nanoparticles can kill bacteria. Figure 6 shows the percentage of bacteria killed by different sized nanoparticles. 6 (a) (i) Give two conclusions ... show full transcript
Worked Solution & Example Answer:Magnesium oxide nanoparticles can kill bacteria - AQA - GCSE Chemistry - Question 6 - 2014 - Paper 1
Step 1
Give two conclusions that can be made from Figure 6.
Answer
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As the size of the nanoparticles increases beyond 8.5 nm, the effectiveness of killing both Type 1 and Type 2 bacteria decreases. Specifically, 100% of Type 1 bacteria are killed with nanoparticles smaller than 7.5 nm, while larger sizes show a decline in effectiveness.
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Type 1 bacteria appear to have a linear relationship while the response of Type 2 bacteria is non-linear, indicating that Type 1 bacteria are more susceptible to the effects of smaller nanoparticles.
Step 2
Would collecting and plotting data for more sizes of nanoparticles improve the conclusions?
Answer
Yes, collecting data for more sizes of nanoparticles would improve the conclusions. It would help confirm the observed pattern of effectiveness and address any anomalies or random errors present in the current dataset. More data could provide a clearer trend and a better line of best fit for analysis.
Step 3
Describe, as fully as you can, what happens when magnesium atoms react with oxygen atoms to produce magnesium oxide.
Answer
When magnesium atoms react with oxygen atoms, magnesium loses two electrons to form Mg²⁺ ions, while oxygen gains two electrons to form O²⁻ ions. This transfer of electrons results in an ionic bond between the magnesium ions and oxide ions, leading to the formation of magnesium oxide (MgO). The resulting compound has a crystalline structure characterized by the electrostatic attraction between the positively charged magnesium ions and the negatively charged oxide ions, which forms a stable lattice arrangement.