Q: The Mars Climate Orbiter was lost due to a failure in unit conversion. If a force was calculated in pounds (lb) but should have been in newtons (N), which conversion factor should have been used to convert pounds to newtons?

$$1 \ \text{lb} = 4.44822 \ \text{N}$$

Question 1

The Mars Climate Orbiter was lost due to a failure in unit conversion. If a force was calculated in pounds (lb) but should have been in newtons (N), which conversion factor should have been used to convert pounds to newtons?

Accepted Answer

$$1 \ 	ext{lb} = 4.44822 \ 	ext{N}$$

Question 2

Which of the following is the correct SI base unit for measuring the amount of substance?

Accepted Answer

Mole (mol)

Question 3

A cube of copper has a mass of $$1.00 \ 	ext{kg}$$ and a density of $$8.96 \ 	ext{g/cm}^3. $$What is the edge length of the cube in centimeters? (1 kg = 1000 g)

Accepted Answer

$$4.81 \ 	ext{cm}$$

Question 4

Which of the following numbers has 3 significant figures?

Accepted Answer

0.00823

Question 5

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

Accepted Answer

Accuracy is how close a measurement is to the true value, while precision is how close repeated measurements are to each other.

Question 6

Convert $$2.50 \ 	ext{m} to $$inches. (1 in = 2.54 cm, 1 m = 100 cm)

Accepted Answer

$$98.4 \ 	ext{in}$$

Question 7

A student records the following masses for a lead block: 10.49 g, 9.79 g, 9.92 g, and 10.31 g. The true mass is 10.00 g. Which best describes the student's measurements?

Accepted Answer

Imprecise and inaccurate

Question 8

Which of the following is an exact number?

Accepted Answer

There are exactly 2.54 cm in 1 inch.

Question 9

What is the density of water in $$	ext{kg/m}^3$$?

Accepted Answer

$$1000 \ 	ext{kg/m}^3$$

Question 10

A car travels 3000 miles and gets 33 miles per gallon. If 1 hogshead = 300 L and 1 gallon = 3.785 L, how many hogsheads of gasoline are needed for the trip?

Accepted Answer

$$1.1$$

Question 11

Which of the following is the correct formula for converting Celsius to Kelvin?

Accepted Answer

$$K = ^\circ C + 273.15$$

Question 12

A measurement is recorded as 0.0540. How many significant figures does it have?

Accepted Answer

3

Question 13

Which of the following is a derived SI unit?

Accepted Answer

Liter (L)

Question 14

If you multiply $$2.0035 (5 $$sig figs) by $$3.20 (3 $$sig figs), how many significant figures should your answer have?

Accepted Answer

3

Question 15

Which prefix represents $$10^{-6} in $$the metric system?

Accepted Answer

Micro ($$\mu)$$

Question 16

A sample of ethanol has a mass of $$78.9 \ 	ext{g}$$ and a volume of $$100.0 \ 	ext{mL}. $$What is its density in $$	ext{g/mL}$$?

Accepted Answer

$$0.789 \ 	ext{g/mL}$$

Question 17

Which of the following best describes the Kelvin temperature scale?

Accepted Answer

It has no negative values and starts at absolute zero.

Question 18

A measurement is recorded as 1050. How many significant figures does it have?

Accepted Answer

2

Question 19

Which of the following is the correct formula for kinetic energy?

Accepted Answer

$$E = \frac{1}{2}mv^2$

Question 20

When performing a multi-step calculation, what is the best practice regarding significant figures?

Accepted Answer

Carry extra digits through the calculation and round only the final answer.

Units, Measurement, and Uncertainty in General Chemistry

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