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Chemical formulae, equations and calculations

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Question 78

Ethane can be obtained from crude oil and converted into many useful substances.

Draw a dot and cross diagram to show the covalent bonding in a molecule of ethane ( $C2H6\text{C}_2\text{H}_6$ ). Only the outer electrons in each atom need to be shown.

[2]

Compound Y can be produced by fermentation and is found in sour milk.

Compound Y contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Calculate the empirical formula of Y.

[3]

The relative formula mass ( $M_r$ ) of Y is 90. What is the molecular formula of Y?

[2]

Markscheme

Chemical formulae, equations and calculations Questions

IGCSE
Chemistry
Chemical formulae, equations and calculations

80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.

Chemical formulae, equations and calculations

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Chemical formulae, equations and calculations

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Question 78

Ethane can be obtained from crude oil and converted into many useful substances.

Draw a dot and cross diagram to show the covalent bonding in a molecule of ethane ( $C2H6\text{C}_2\text{H}_6$ ). Only the outer electrons in each atom need to be shown.

[2]

Compound Y can be produced by fermentation and is found in sour milk.

Compound Y contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Calculate the empirical formula of Y.

[3]

The relative formula mass ( $M_r$ ) of Y is 90. What is the molecular formula of Y?

[2]

Markscheme

Chemical formulae, equations and calculations Questions

IGCSE
Chemistry
Chemical formulae, equations and calculations

80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.