Q: A student records the following measurements for the density of a material: 1.20 g/mL, 1.22 g/mL, 1.22 g/mL. The true value is 1.15 g/mL. What is the percent error of the average measurement?

$$\frac{|1.21 - 1.15|}{1.15} \times 100 = 5.2\%$$

Q: A student needs to convert 8.0 cm$$^2 to m$^2. $$Which is the correct conversion factor to use?

$$\frac{1 \text{ m}^2}{10^4$ \text{ cm}^2}$$

Question 1

Which of the following best explains why you should always estimate one digit beyond the smallest graduation on a measuring instrument?

Accepted Answer

Because the last digit is always estimated, reflecting the uncertainty in the measurement and maximizing the precision allowed by the instrument.

Question 2

A student measures the mass of a sample three times and records 5.00 g, 5.01 g, and 5.00 g. The true mass is 5.50 g. Which statement best describes the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following is a qualitative observation?

Accepted Answer

The solution is yellow and cloudy.

Question 4

A graduated cylinder is used to measure the volume of a liquid. The meniscus is at 36.5 mL. Which is the correct way to read the volume?

Accepted Answer

Read from the bottom of the meniscus at eye level.

Question 5

Convert 2.76 dm to km using dimensional analysis.

Accepted Answer

$$2.76 	imes 10$$^{-4}$$ km

Question 6

Which of the following numbers has 4 significant figures?

Accepted Answer

1.008

Question 7

A metal has a mass of 57.3 g and a volume of 4.75 cm$$^3. $$What is its density?

Accepted Answer

$$12.1 g/cm$^3$$

Question 8

Which of the following best describes the difference between accuracy and precision?

Accepted Answer

Accuracy refers to how close measurements are to the true value, while precision refers to how close measurements are to each other.

Question 9

Which of the following is the correct scientific notation for 5783000000 m?

Accepted Answer

$$5.783 	imes 10$$^{9}$$ m

Question 10

A student records the following measurements for the density of a material: 1.20 g/mL, 1.22 g/mL, 1.22 g/mL. The true value is 1.15 g/mL. What is the percent error of the average measurement?

Accepted Answer

$$\frac{|1.21 - 1.15|}{1.15} 	imes 100 = 5.2\%$$

Question 11

Which of the following is NOT a criterion for a claim to be considered scientific?

Accepted Answer

It must be based on personal beliefs.

Question 12

When converting units using dimensional analysis, which of the following is true?

Accepted Answer

The units you want to cancel should be placed on the bottom in the conversion factor.

Question 13

A student needs to convert 8.0 cm$$^2 to m$^2. $$Which is the correct conversion factor to use?

Accepted Answer

$$\frac{1 	ext{ m}^2}{10^4$ 	ext{ cm}^2}$$

Question 14

Which of the following best describes the correct way to determine the slope of a line on a graph?

Accepted Answer

Choose two points on the best fit line and calculate $$\frac{\Delta y}{\Delta x}.$$

Question 15

Which of the following numbers has 5 significant figures?

Accepted Answer

14.600

Question 16

A student weighs a 5 lb bag of potatoes three times and gets 3.5 lb, 4.1 lb, and 4.2 lb. Which statement best describes these measurements?

Accepted Answer

They are neither accurate nor precise.

Question 17

Which of the following is the correct scientific notation for 0.00321 g?

Accepted Answer

$$3.21 	imes 10$$^{-3}$$ g

Question 18

Which of the following best explains why the number of graduations on a measuring instrument affects the accuracy of your measurement?

Accepted Answer

More graduations allow for a more precise estimation of the measured value.

Question 19

A piece of lead has a volume of 12.0 cm$$^3$$ and the density of lead is 11.4 g/cm$$^3. $$What is the mass of the lead?

Accepted Answer

$$137 g$$

Introduction to Chemistry: Measurement, Observations, and Scientific Method

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