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Covalent substances can be simple molecular covalent or giant covalent - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2018 - Paper 1
Question 5
Covalent substances can be simple molecular covalent or giant covalent. (i) Ammonia is a simple molecular, covalent substance. Which is the most likely set of prope... show full transcript
Worked Solution & Example Answer:Covalent substances can be simple molecular covalent or giant covalent - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2018 - Paper 1
Step 1
Which is the most likely set of properties for ammonia?
Answer
The most likely set of properties for ammonia is option B:
- Melting point: −78 °C
- Boiling point: −33 °C
- Ability to conduct electricity in liquid state: does not conduct.
This is because ammonia is a simple molecular substance, which typically has low melting and boiling points and does not conduct electricity.
Step 2
Step 3
Draw a dot and cross diagram for the molecule of oxygen.
Answer
The dot and cross diagram for the oxygen molecule (O₂) is illustrated below:
O: ••
O: ••
In this diagram, each dot represents an electron from one oxygen atom, while each cross represents an electron from the other oxygen atom. The molecule features a double bond between the two oxygen atoms.