S1 3/1 - Lab Apparatus, Accuracy, Precision and Errors

What does this symbol represent?

• beaker

• conical flask

• round bottom flask

• tripod stand

Which of the following correctly states the purpose of the apparatus shown in the diagram below?

• used to contain a solution to be heated

• used to hold liquid or solid samples undergoing a reaction

• used to measure the volume of a liquid

• used to support glassware such as beakers and flasks

Answer explanation

Which of the following measure(s) of error is/are correctly matched to their definitions?

Select all that apply.

• A

• B

• C

• D

Answer explanation

A measurement is accurate if it is very close to the true value of the object.

If multiple readings taken are very close to one another or the same, the measurements are said to be precise.

Which of these is not a way to improve the accuracy of your readings?

• If an electronic balance displays a zero error, ensure that it is corrected for.

• Position the eye so that the line of sight is perpendicular to the marking on the ruler.

• Repeat the experiment multiple times.

• When taking a reading using a mercury thermometer, position the eye so that the line of sight is level with the top of the meniscus.

Answer explanation

To improve the accuracy of our readings, we need to minimise zero errors, parallax errors and human errors.

Repeating the experiment multiple times does not improve the accuracy of our readings because we could repeat the same type of error again and again with each reading taken. Doing so would not get our measurements closer to the true value.

Which of the following errors is identified correctly?

• A

• B

• C

• D

Answer explanation