Expert Chemistry Tutoring

Q1. Knowledge Recall (1 mark)

Define the term fractional distillation and state one industry where it is used.

Q2. Application (2 marks)

Explain why pure water is a good electrical insulator.

Q3. Data Analysis (3 marks)

A mixture of water and ethanol has a boiling point of 82°C. Use the phase diagram below to determine the percentage of ethanol in the mixture.

[Image of water-ethanol phase diagram]

Q4. Calculations (3 marks)

Calculate the mass of sodium hydroxide required to neutralize 100 cm³ of 0.25 mol/dm³ sulfuric acid.

Q5. Application (2 marks)

Describe the process of recrystallization and explain why it is used to purify substances.

Q6. Chemical Equation (3 marks)

Write a balanced chemical equation for the reaction between sodium carbonate and hydrochloric acid.

Q7. Knowledge Recall (2 marks)

Define the term "percent purity" and give one method for determining it.

Q8. Application (2 marks)

Explain why it is important to use pure starting materials when preparing a substance.

Q9. Calculations (4 marks)

A 5.00 g sample of impure calcium carbonate contains 2.00 g of calcium oxide. Calculate the percentage purity of the calcium carbonate sample.

Q10. Real-World Context (4 marks)

Discuss the importance of using pure medications in healthcare and the potential consequences of using contaminated or impure drugs.