### Question 1

**Which of the following best describes a systematic error?**

A. An error that occurs unpredictably and without a consistent pattern.

B. An error that arises due to faulty equipment or incorrect calibration.

C. An error that can be reduced by taking multiple measurements.

D. An error that arises due to the limitations of human observation.

### Question 2

**What is the primary difference between accuracy and precision?**

A. Accuracy refers to how close a measurement is to the true value, while precision refers to how close repeated measurements are to each other.

B. Accuracy refers to how close repeated measurements are to each other, while precision refers to how close a measurement is to the true value.

C. Accuracy and precision both refer to how close a measurement is to the true value.

D. Accuracy and precision both refer to how close repeated measurements are to each other.

### Question 3

**Which of the following is a common source of random error?**

A. Faulty equipment

B. Incorrect calibration of an instrument

C. Fluctuations in experimental conditions

D. Biased data recording

### Question 4

**If the absolute uncertainty in a measurement is 0.5 and the measurement itself is 10, what is the relative uncertainty?**

A. 0.05

B. 0.005

C. 5%

D. 50%

### Question 5

**When adding or subtracting quantities, how is the absolute uncertainty determined?**

A. By adding the absolute uncertainties of the quantities.

B. By subtracting the absolute uncertainties of the quantities.

C. By multiplying the absolute uncertainties of the quantities.

D. By dividing the absolute uncertainties of the quantities.

### Question 6

**a)** Define systematic errors and provide an example of a cause for such an error in a chemistry experiment. [2]

**b)** Explain how systematic errors can be corrected in experiments. [2]

### Question 7

**a)** Differentiate between accuracy and precision in the context of experimental measurements. [2]

**b)** If a student repeats an experiment five times and gets values very close to each other but far from the accepted value, is the student's data accurate, precise, or both? Justify your answer. [2]

### Question 8

**a)** What is meant by absolute uncertainty in the context of experimental measurements? [2]

**b)** A student measures the volume of a liquid as 50.0 ± 0.5 mL. What is the relative uncertainty of this measurement? [2]

### Question 9

**a) **Describe the main causes of random errors in a chemistry experiment. [2]

**b)** How can random errors be minimised in experimental measurements? [2]

**c)** If a student repeats an experiment multiple times and observes varying results, what type of error is likely responsible? [2]

### Question 10

**a)** Explain the difference between absolute and relative uncertainty. [3]

**b)** A student measures the mass of a sample as 20.0 ± 0.2 g. Calculate the relative uncertainty of this measurement. [2]

**c) **Why is it important to consider relative uncertainty when comparing results from different experiments? [2]

### Question 11

**Which of the following best describes how to minimise random errors?**

A. Calibrate the equipment regularly.

B. Use more advanced equipment.

C. Take multiple measurements and calculate an average.

D. Follow a strict experimental procedure.

### Question 12

**In an experiment, if the calculated result is 20.5 and the accepted value is 21.0, which of the following statements is true?**

A. The result is precise but not accurate.

B. The result is accurate but not precise.

C. The result is both accurate and precise.

D. The result is neither accurate nor precise.

### Question 13

**Which type of error is most likely to be introduced by a biased observer?**

A. Systematic error

B. Random error

C. Absolute error

D. Relative error

### Question 14

**If the relative uncertainty in a measurement is 2% and the measurement itself is 50, what is the absolute uncertainty?**

A. 1

B. 0.02

C. 2.5

D. 0.5

### Question 15

**When multiplying or dividing quantities, how is the relative uncertainty determined?**

A. By adding the relative uncertainties of the quantities.

B. By subtracting the relative uncertainties of the quantities.

C. By multiplying the relative uncertainties of the quantities.

D. By dividing the relative uncertainties of the quantities.

### Question 16

**a)** What is meant by the term "propagation of uncertainty"? [3]

**b)** If two quantities with uncertainties are multiplied or divided, how is the uncertainty in the result determined? [2]

**c)** Why is it crucial to consider the propagation of uncertainty when combining results from different measurements in calculations? [2]

### Question 17

**a)** Describe the significance of including error bars in graphical representations of data. [3]

**b)** How can the gradient of a graph be used to determine the relationship between two variables in an experiment? [2]

**c) **If a graph's y-intercept has a significant value, what does this indicate about the experiment or the relationship between the variables? [2]

### Question 18

**a) **Define systematic errors and provide two examples of such errors in a chemistry laboratory setting. [3]

**b) **How do systematic errors differ from random errors in terms of their effect on experimental results? [2]

**c)** A student uses a balance that has not been zeroed correctly to measure out a sample. What type of error is this, and how can it be corrected? [2]

**d) **Why is it important to identify and correct systematic errors before repeating an experiment multiple times? [3]

### Question 19

**a)** Describe the difference between accuracy and precision in the context of experimental measurements. [3]

**b)** If a set of measurements are close to each other but far from the true value, how would you describe their accuracy and precision? [2]

**c)** Explain the significance of relative uncertainty when comparing the reliability of two different measurements. [3]

**d)** A student calculates the relative uncertainty of two measurements as 5% and 2%. Which measurement is more reliable and why? [2]

### Question 20

**a)** What are the primary sources of uncertainty in measurements taken in a chemistry experiment? [3]

**b)** How can the propagation of uncertainty be considered when combining results from different measurements in calculations? [3]

**c)** If two measurements with uncertainties are added or subtracted, how is the uncertainty in the result determined? [2]

**d) **Why is it essential to consider both absolute and relative uncertainties when interpreting experimental results? [2]