Q: Which of the following is the correct formula for calculating percent error?

$$\frac{\lvert \text{theoretical} - \text{experimental} \rvert}{\text{theoretical}} \times 100$$

Question 1

Which of the following best defines accuracy in scientific measurements?

Accepted Answer

The closeness of a measurement to the true or accepted value.

Question 2

A student measures the mass of a sample three times and records 2.01 g, 2.00 g, and 2.02 g. The true mass is 2.50 g. Which statement is correct about the data?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following is the correct formula for calculating percent error?

Accepted Answer

$$\frac{\lvert 	ext{theoretical} - 	ext{experimental} vert}{	ext{theoretical}} 	imes 100$$

Question 4

A chemistry student obtained an experimental yield of 1.8 grams when the theoretical yield was 2.0 grams. What is the percent error?

Accepted Answer

$$10\%$$

Question 5

Which of the following statements about significant figures is TRUE?

Accepted Answer

The number of significant figures depends on the measuring instrument used.

Question 6

Which SI base unit is used to measure temperature?

Accepted Answer

Kelvin

Question 7

Convert $$30\ ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$303\ \mathrm{K}$$

Question 8

Which of the following is the best SI unit to measure the mass of a grain of rice?

Accepted Answer

Milligram

Question 9

A conversion factor is best described as:

Accepted Answer

A ratio of equivalent measurements used to convert between units.

Question 10

Which of the following is an example of dimensional analysis?

Accepted Answer

Converting 5 kilometers to meters using $$1\ \mathrm{km} = 1000\ \mathrm{m}.$$

Question 11

If you have $$250\ \mathrm{mg} of a $$substance, how many grams do you have?

Accepted Answer

$$0.25\ \mathrm{g}$$

Question 12

Which of the following best describes density?

Accepted Answer

The ratio of mass to volume.

Question 13

What is the formula for density?

Accepted Answer

$$d = \frac{m}{V}$$

Question 14

A cube has a mass of $$54\ \mathrm{g}$$ and a volume of $$18\ \mathrm{cm}^3. $$What is its density?

Accepted Answer

$$3.0\ \mathrm{g/cm}^3$$

Question 15

Which statement about density is correct?

Accepted Answer

Density is an intensive property that does not depend on the amount of substance.

Question 16

Which of the following is the correct scientific notation for 0.000042?

Accepted Answer

$$4.2 	imes 10$$^{-5}$$

Question 17

Which SI unit and prefix would be most appropriate to measure the diameter of a marble?

Accepted Answer

Centimeter

Question 18

Which of the following is TRUE about conversion factors?

Accepted Answer

The measurement in the numerator is equal to the measurement in the denominator.

Question 19

A sample of gold has a density of $$19.3\ \mathrm{g/cm}^3$$ and a sample of aluminum has a density of $$2.7\ \mathrm{g/cm}^3. $$Which is denser?

Accepted Answer

Gold

Question 20

Which of the following statements about the Celsius and Kelvin temperature scales is correct?

Accepted Answer

Absolute zero is $$0\ \mathrm{K}$$, which is $$-273.15\ ^\circ\mathrm{C}.$$

Chapter 3: Measurements, Units, and Problem Solving in Chemistry

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