Q: Which of the following is a correct conversion between centimeters and millimeters?

$$1 \text{ cm} = 10 \text{ mm}$$

Q: A student is asked to convert 0.25 grams to milligrams. Which of the following is the correct conversion?

$$0.25 \text{ g} \times 1000 = 250 \text{ mg}$$

Question 1

Which of the following is the best definition of 'accuracy' in the context of laboratory measurements?

Accepted Answer

The closeness of a measured value to a standard or known value.

Question 2

A student measures the mass of 1 mL of water five times using a P1000 micropipette and records the following values (in mg): 995, 997, 996, 998, 996. What is the range of these measurements?

Accepted Answer

$$998 - 995 = 3 mg$$

Question 3

Which of the following best describes the difference between a beaker and a graduated cylinder when measuring liquid volume?

Accepted Answer

A graduated cylinder is designed for more accurate and precise volume measurements than a beaker.

Question 4

A student is using a micropipette labeled P1000. What is the maximum volume (in microliters) that this pipette can accurately measure?

Accepted Answer

$$1000$$ \mu L$

Question 5

If a student spills a chemical on their skin during a lab, what is the FIRST action they should take?

Accepted Answer

Immediately rinse the affected area with water.

Question 6

Which of the following is a correct conversion between centimeters and millimeters?

Accepted Answer

$$1 	ext{ cm} = 10 	ext{ mm}$$

Question 7

A student uses a serological pipette to measure 1 mL of water five times and gets the following masses (in mg): 1005, 1002, 1008, 1001, 1004. The expected value is 1000 mg. What is the mean (average) of these measurements?

Accepted Answer

$$\frac{1005 + 1002 + 1008 + 1001 + 1004}{5} = 1004 mg$$

Question 8

Which of the following best describes the meniscus and how it should be read when measuring liquid volume in a graduated cylinder?

Accepted Answer

The meniscus is the curved surface of the liquid and should be read at the bottom of the curve at eye level.

Question 9

A student is comparing the accuracy of two pipettes. The expected value for 1 mL of water is 1000 mg. The student calculates the average value for the P1000 micropipette as 995 mg and for the serological pipette as 1004 mg. Which pipette is more accurate and why?

Accepted Answer

The serological pipette, because $$|1000 - 1004| = 4 mg is $$less than $$|1000 - 995| = 5 mg.$$

Question 10

Which of the following is NOT a recommended lab safety practice?

Accepted Answer

Eating snacks at your lab bench during an experiment.

Question 11

A student is asked to convert 0.25 grams to milligrams. Which of the following is the correct conversion?

Accepted Answer

$$0.25 	ext{ g} 	imes 1000 = 250 	ext{ mg}$$

Question 12

Which of the following best describes the relationship between mass and volume for water at room temperature?

Accepted Answer

The mass (in grams) is approximately equal to the volume (in mL).

Question 13

A student is using a triple beam balance to measure the mass of a sample. Which of the following steps should they take to ensure an accurate measurement?

Accepted Answer

Zero the balance before placing the sample on the pan.

Question 14

Which of the following scenarios best demonstrates high precision but low accuracy?

Accepted Answer

A student measures the mass of a 1 g standard five times and gets: 0.80 g, 0.81 g, 0.80 g, 0.81 g, 0.80 g.

Question 15

When using a micropipette, why is it important not to turn the indicator dial beyond the upper or lower limit?

Accepted Answer

It can damage the piston and affect the accuracy of the pipette.

Question 16

A student is asked to calculate the absolute value of the difference between the expected value and the average value for a set of measurements. Which formula should they use?

Accepted Answer

$$|	ext{Expected Value} - 	ext{Average Value}|$$

Question 17

Which of the following is a real-world example of cohesion in water?

Accepted Answer

Water droplets forming beads on a waxed car hood.

Question 18

A student is instructed to use a digital balance to measure the mass of a liquid. What is the correct procedure?

Accepted Answer

Place the empty container on the balance, tare it, then add the liquid and record the mass.

Introduction to Laboratory Skills and Safety in General Biology

Study Guide - Practice Questions

Study Guide - Flashcards