Practice questions: Introduction to Chemistry

Try each question with the answers covered, then check your response and the one-line reason. These are original questions written in the style of Paper 1 (4541/1), not past-year papers. Attempt the multiple-choice section first, then the structured questions, and mark yourself honestly.

Section A, Multiple-choice questions

1. A student changes the concentration of acid and measures how quickly a gas is produced. Which is the manipulated variable?

• A. Volume of gas produced
• B. Concentration of the acid
• C. Temperature of the acid
• D. Mass of the metal

Answer: B, it is the quantity the student deliberately changes.

2. Which of the following is a suitable hypothesis?

• A. To investigate the effect of temperature on reaction rate
• B. Temperature is an important factor
• C. The higher the temperature, the faster the reaction
• D. Water boils at 100 °C

Answer: C, it predicts a testable relationship between two variables.

3. In a test, a colourless gas is produced. Which statement is an inference, not an observation?

• A. A colourless gas is released
• B. The gas turns limewater milky
• C. The gas is carbon dioxide
• D. Bubbles form in the solution

Answer: C, naming the gas is a conclusion drawn from the observations.

4. Which apparatus delivers an accurate, fixed volume of 25.0 cm³ of solution?

• A. Beaker
• B. Measuring cylinder
• C. Pipette
• D. Conical flask

Answer: C, a pipette delivers one accurate, known volume; the others are approximate.

5. Which instrument is used to measure the mass of a solid?

• A. Thermometer
• B. Electronic balance
• C. Burette
• D. Stopwatch

Answer: B, mass is measured with a balance, in grams.

6. When reading the volume of liquid in a burette, the eye should be:

• A. Above the meniscus
• B. Level with the bottom of the meniscus
• C. Level with the top of the meniscus
• D. Below the meniscus

Answer: B, reading level with the bottom of the meniscus avoids parallax error.

7. A reagent bottle carries a corrosive hazard symbol. Which is the best precaution?

• A. Taste a small amount to identify it
• B. Wear safety goggles and handle it carefully
• C. Smell it directly to confirm it
• D. Pour any excess down the sink

Answer: B, corrosive chemicals damage on contact, so protect the eyes and skin.

8. Why should you waft the smell of a chemical towards you rather than smell it directly?

• A. To save time
• B. To avoid being overcome by concentrated fumes
• C. To warm the vapour
• D. To see its colour

Answer: B, wafting gives a faint, safe amount of vapour.

9. What is the correct way to deal with a small amount of leftover acid?

• A. Pour it down the sink
• B. Dispose of it as instructed, in the labelled waste container
• C. Throw the bottle in the bin
• D. Leave it on the bench

Answer: B, chemicals must be disposed of as instructed to protect drains and the environment.

10. Which is an example of chemistry in daily life?

• A. The reflection of light from a mirror
• B. The preservation of food using chemicals
• C. The force of a moving car
• D. The echo of sound in a hall

Answer: B, food preservation relies on chemical action; the others are physics.

Section B, Structured questions

Question 1 (Scientific method). A student investigates how the surface area of marble chips affects the time taken for them to react completely with dilute hydrochloric acid. Large chips, medium chips and powder are used.

• (a) State the manipulated variable.
• (b) State the responding variable.
• (c) State two controlled variables.
• (d) Write a suitable hypothesis.

Model answer.

• (a) The surface area of the marble chips (their size).
• (b) The time taken for the marble to react completely.
• (c) The volume and concentration of the hydrochloric acid; the mass of marble used; the temperature (any two).
• (d) “The larger the surface area of the marble, the shorter the time taken to react completely.” The hypothesis names both variables and predicts the direction of the relationship.

Question 2 (Apparatus and safety). A student must measure exactly 25.0 cm³ of sodium hydroxide solution and heat it gently in a test tube.

• (a) Name the apparatus used to measure 25.0 cm³ accurately, and give a reason for your choice.
• (b) State one safety precaution when heating the liquid, and give a reason.

Model answer.

• (a) A pipette, because it delivers an accurate, known, fixed volume; a measuring cylinder would give only an approximate volume.
• (b) Point the mouth of the test tube away from yourself and others, so that if the liquid spurts out no one is scalded. (Also acceptable: wear safety goggles, because sodium hydroxide is corrosive and can damage the eyes.)

Question 3 (Chemistry in daily life and careers).

• (a) Give two examples of how chemistry is used in daily life, and state what the chemistry does in each.
• (b) Name one career that uses chemistry and explain the link.

Model answer.

• (a) In medicine, chemistry is used to develop and manufacture drugs such as painkillers that treat illness; in agriculture, chemical fertilisers supply nutrients that help crops grow. (Other valid pairs: food preservation slowing spoilage; fuels burning to release energy.)
• (b) A pharmacist prepares and dispenses medicines and advises patients on their safe use, the whole role depends on understanding the chemistry of the drugs.

How to use these questions

Mark every answer against the reason given, not just the letter. In the structured questions, check that you named a measurable responding variable, chose apparatus that matched the accuracy needed, and paired each safety precaution with a reason, the three places this chapter awards or removes marks. If two or three answers slipped for the same reason, that is the habit to drill next. A one-to-one teacher can work through your structured answers line by line and show exactly where a mark was earned or lost before you sit the SPM Chemistry papers.