Q: A laboratory balance reads a mass as 0.00450 kg. Express this value in scientific notation and identify the number of significant figures.

$$4.50 \times 10$$^{-3}$$ kg; 3 significant figures

Q: A cube has a side length of $$2.0 m. $$What is its volume in mm$$^3$$? (1 m = 1000 mm)

$$8.0 \times 10^9$ \text{ mm}^3$

Question 1

A laboratory balance reads a mass as 0.00450 kg. Express this value in scientific notation and identify the number of significant figures.

Accepted Answer

$$4.50 	imes 10$$^{-3}$$ kg; 3 significant figures

Question 2

A student measures the length of a metal rod as 12.36 cm using a ruler marked in millimeters. Which digit is the estimated value in this measurement?

Accepted Answer

The '6' in 12.36 cm

Question 3

Which of the following numbers has exactly three significant figures?

Accepted Answer

3.40 	imes $$10^2$$

Question 4

When multiplying $$2.34 (3 $$significant figures) by $$1.2 (2 $$significant figures), how many significant figures should the answer have?

Accepted Answer

2

Question 5

Round the number 0.006789 to three significant figures.

Accepted Answer

0.00679

Question 6

Which of the following is the correct SI unit for measuring electric current?

Accepted Answer

Ampere (A)

Question 7

A distance is measured as 5.6 km. Express this value in meters using the correct prefix conversion.

Accepted Answer

$$5.6 	imes 10^3$ m

Question 8

Convert 250 mL to liters using dimensional analysis.

Accepted Answer

$$0.250 L$$

Question 9

A rectangular aquarium has dimensions 80.0 cm × 35.0 cm × 40.0 cm. What is its volume in liters? (1 L = 1000 cm$$^3)$$

Accepted Answer

$$112.0 L$$

Question 10

A car travels 60.0 miles per hour. Convert this speed to meters per second. (1 mile = 1.609 km)

Accepted Answer

$$26.8 m/s$$

Question 11

The area of a square is measured as $$2.5 m$^2. $$Convert this area to cm$$^2$$ using dimensional analysis.

Accepted Answer

$$25000$$ 	ext{ cm}^2$

Question 12

A sample of metal has a mass of 13.5 g and a volume of 5.0 cm$$^3. $$What is its density?

Accepted Answer

$$2.7$$ 	ext{ g/cm}^3$

Question 13

A liquid has a density of $$0.789 g/mL. $$What is the mass of $$250 mL of $$this liquid?

Accepted Answer

$$197.25 g$$

Question 14

A gold bar has a mass of $$1.00 kg $$and a density of $$19.3 g/cm$^3. $$What is its volume in cm$$^3$$?

Accepted Answer

$$51.8$$ 	ext{ cm}^3$

Question 15

A medication is prescribed at a dose of $$5.0 mg/kg. If a $$patient weighs $$70 kg$$, how many grams of medication should be administered?

Accepted Answer

$$0.35 g$$

Question 16

Which of the following statements about significant figures is correct?

Accepted Answer

All zeros to the right of the decimal point and after a nonzero digit are significant.

Question 17

A student records a temperature as $$2.00 	imes 10^2$ K. How many significant figures does this measurement have?

Accepted Answer

3

Question 18

A cube has a side length of $$2.0 m. $$What is its volume in mm$$^3$$? (1 m = 1000 mm)

Accepted Answer

$$8.0 	imes 10^9$ 	ext{ mm}^3$

Question 19

A solution has a density of $$1.10 g/mL. $$What is the volume in liters of $$550 g of $$this solution?

Accepted Answer

$$0.605 L$$

Question 20

A chemist needs to prepare $$250 mL of a $$solution. If the graduated cylinder used has markings every $$1 mL$$, to how many significant figures should the volume be recorded?

Accepted Answer

3

Measurement, Significant Figures, and Unit Conversions in Chemistry

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