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3 (a) Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Chemistry - Question 3 - 2013 - Paper 1
Question 3
3 (a) Complete the sentence by putting a cross (X) in the box next to your answer. A mixture of two immiscible liquids can be separated by using □ A fractional dis... show full transcript
Worked Solution & Example Answer:3 (a) Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Chemistry - Question 3 - 2013 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
Answer
The correct method for separating a mixture of two immiscible liquids is to use a separating funnel (B). This method allows for the effective separation of two layers of liquids that do not mix, such as oil and water.
Step 2
(i) Draw a dot and cross diagram for a molecule of oxygen, O₂.
Answer
To draw the dot and cross diagram for the oxygen molecule (O₂):
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Each oxygen atom has 6 outer electrons (2 in the first shell and 4 in the outer shell).
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Represent the electrons from one oxygen atom with dots (•) and the electrons from the other oxygen atom with crosses (×).
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Join the two oxygen atoms sharing two pairs of electrons, forming a double bond:
O• •O
O× ×O
This shows the shared electrons between the two oxygen atoms.