MEDIUM
Upper Secondary: IGCSE
IMPORTANT
Earn 100

Use your copy of the periodic table to help you answer the question.

Fluorine and astatine are halogens. Use your knowledge of the other halogens to predict the similarities in chemical properties of fluorine and astatine.

Important Questions on Cambridge IGCSE Exam Questions from Paper 3

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

Across the world, food safety agencies are investigating the presence of minute traces of the toxic hydrocarbon, benzene, in soft drinks. It is formed by the reduction of sodium benzoate by vitamin C.

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Sodium benzoate is a salt. It has the formula C6H5COONa. It can be made by neutralising benzoic acid using sodium hydroxide. Deduce the formula of benzoic acid.

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

Across the world, food safety agencies are investigating the presence of minute traces of the toxic hydrocarbon, benzene, in soft drinks. It is formed by the reduction of sodium benzoate by vitamin C.

Question Image

Sodium benzoate is a salt. It has the formula C6H5COONa. It can be made by neutralising benzoic acid using sodium hydroxide. Write the word equation for the reaction between benzoic acid and sodium hydroxide.

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

Across the world, food safety agencies are investigating the presence of minute traces of the toxic hydrocarbon, benzene, in soft drinks. It is formed by the reduction of sodium benzoate by vitamin C.

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Sodium benzoate is a salt. It has the formula C6H5COONa. It can be made by neutralising benzoic acid using sodium hydroxide. Name two other compounds that would react with benzoic acid to form sodium benzoate.

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

Benzene conatins 92.3% of carbon and its relative molecular mass is 78. What is the percentage of hydrogen in benzene?

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

Benzene contains 92.3% of carbon and its relative molecular mass is 78. Calculate the ratio of moles of C atoms: moles of H atoms in benzene.

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

Benzene conatins 92.3% of carbon and its relative molecular mass is 78. Calculate the empirical formula and molecular formula of benzene.

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

This shows the structural formula of Vitamin C.

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What is its molecular formula?

MEDIUM
Upper Secondary: IGCSE
IMPORTANT

This shows the structural formula of Vitamin C.

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Name the two functional groups that are circled.