7 (a)
Silicon dioxide has a very high melting point - AQA - GCSE Chemistry - Question 7 - 2014 - Paper 1
Question 7
7 (a)
Silicon dioxide has a very high melting point.
Other substances are added to silicon dioxide to make glass. Glass melts at a lower temperature than silicon dio... show full transcript
Worked Solution & Example Answer:7 (a)
Silicon dioxide has a very high melting point - AQA - GCSE Chemistry - Question 7 - 2014 - Paper 1
Step 1
Suggest why glass melts at a lower temperature than silicon dioxide.
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Answer
The addition of other substances to silicon dioxide results in weaker bonds or fewer forces within the structure. These weaker interactions require less energy to overcome, allowing the glass to melt at a lower temperature.
Step 2
Give the formula of sodium oxide.
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Answer
The formula for sodium oxide is Na2O.
Step 3
Complete the diagram to show the outer electrons in an oxygen molecule (O2).
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Answer
The diagram should show two oxygen atoms, each with 6 outer electrons. They should have 2 bonding pairs (shared electrons) and 2 lone pairs on each oxygen atom.
Step 4
Describe the structure of a metal.
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Answer
Metals have a lattice structure composed of closely packed atoms. The metal structure consists of positive ions surrounded by a 'sea' of delocalised or free electrons. This arrangement allows for conductivity and malleability.
