Q: Which of the following is the correct formula for calculating the density ($$d) of a $$substance?

$$d = \dfrac{\text{mass}}{\text{volume}}$$

Q: Which of the following statements about percent error is correct?

Percent error is calculated as $$\dfrac{\text{experimental value} - \text{accepted value}}{\text{accepted value}} \times 100\%.$$

Question 1

Which of the following best describes the term 'significant figures' in a measurement?

Accepted Answer

All the digits in a measurement that are known with certainty plus one final digit that is estimated.

Question 2

A student measures the mass of a sample as $$45.34\ \mathrm{g}$$ using a balance. Which of the following statements about the measurement is correct?

Accepted Answer

The last digit (4) is uncertain and estimated.

Question 3

You are asked to measure the volume of a liquid in a graduated cylinder. Which of the following is the correct procedure?

Accepted Answer

Read the volume at the bottom of the meniscus at eye level.

Question 4

Which of the following is NOT a physical quantity that can be measured in the laboratory?

Accepted Answer

Color

Question 5

A student records the following measurements for the mass of a sample: $$12.34\ \mathrm{g}$$, $$12.36\ \mathrm{g}$$, and $$12.35\ \mathrm{g}. $$The true mass is $$12.50\ \mathrm{g}. $$Which statement best describes the data?

Accepted Answer

The measurements are precise but not accurate.

Question 6

Which of the following is the correct formula for calculating the density ($$d) of a $$substance?

Accepted Answer

$$d = \dfrac{	ext{mass}}{	ext{volume}}$$

Question 7

A student measures the mass of a rock as $$85.0\ \mathrm{g}$$ and its volume as $$32.0\ \mathrm{mL}. $$What is the density of the rock, reported with the correct number of significant figures?

Accepted Answer

$$2.66\ \mathrm{g/mL}$$

Question 8

Which of the following best describes how to determine the density of an irregularly shaped solid?

Accepted Answer

Measure its mass and determine its volume by liquid displacement.

Question 9

A student creates a graph of mass (y-axis) versus volume (x-axis) for several samples of the same substance. What does the slope of the best-fit line represent?

Accepted Answer

The density of the substance.

Question 10

Which of the following is NOT a criterion for a well-made scientific graph?

Accepted Answer

Data points are connected with a smooth curve regardless of trend.

Question 11

A student measures the mass of a beaker as $$55.67\ \mathrm{g}$$, then adds a sample and finds the total mass is $$78.12\ \mathrm{g}. $$What is the mass of the sample, reported with the correct number of significant figures?

Accepted Answer

$$22.45\ \mathrm{g}$$

Question 12

Which of the following statements about percent error is correct?

Accepted Answer

Percent error is calculated as $$\dfrac{	ext{experimental value} - 	ext{accepted value}}{	ext{accepted value}} 	imes 100\%.$$

Question 13

Which of the following measurements contains the greatest number of significant figures?

Accepted Answer

$$0.019$$

Question 14

When measuring the mass of a sample using a container (such as a weighing boat), what is the correct procedure?

Accepted Answer

Subtract the mass of the empty container from the total mass to get the sample mass.

Question 15

Which of the following is a correct statement about uncertainty in measurements?

Accepted Answer

Uncertainty is represented by the last significant digit in a measurement.

Question 16

A student calculates the density of a liquid as $$1.85\ \mathrm{g/mL}$$ using a mass of $$18.5\ \mathrm{g}$$ and a volume of $$10.0\ \mathrm{mL}. If $$the accepted density is $$1.90\ \mathrm{g/mL}$$, what is the percent error?

Accepted Answer

$$2.6\%$$

Question 17

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; precision refers to how close measurements are to each other.

Question 18

Which of the following is a correct way to report the result of a calculation involving multiplication of measured values?

Accepted Answer

The result should have as many significant figures as the measurement with the fewest significant figures.

Question 19

A student is asked to graph the relationship between the volume and mass of a metal. Which variable should be placed on the x-axis?

Accepted Answer

Volume

Question 20

Which of the following is NOT a correct unit for density?

Accepted Answer

$$\mathrm{mL/g}$$

Measurement, Significant Figures, and Density in Chemistry

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