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

$$\text{Density} = \frac{\text{Mass}}{\text{Volume}}$$

Question 1

Which statement best describes the difference between accuracy and precision in scientific measurements?

Accepted Answer

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

Question 2

A student measures the mass of a standard 100.00 g weight on two different balances. Balance A reads 100.00 g every time, while Balance B reads 98.89 g, 101.09 g, and 99.99 g. Which balance is more accurate and which is more precise?

Accepted Answer

Balance A is more accurate and more precise.

Question 3

Given the following measurements for the density of aluminum (true value = 2.7 g/mL):
A: 2.924, 2.923, 2.925, 2.926
B: 2.316, 2.527, 2.941, 2.136
C: 2.649, 2.731, 2.695, 2.742
D: 2.701, 2.699, 2.702, 2.698
Which set is both accurate and precise?

Accepted Answer

Set D

Question 4

Calculate the percent error for a student who measures the temperature of a solution to be 79°C, while the true temperature is 85°C. Use the formula $$	ext{Percent Error} = \frac{	ext{Experimental Value} - 	ext{True Value}}{	ext{True Value}} 	imes 100\%.$$

Accepted Answer

$$7.1\%$$

Question 5

How many significant figures are in the number $$0.0101$$?

Accepted Answer

3

Question 6

Which of the following numbers has 4 significant figures?

Accepted Answer

$$0.1000$$

Question 7

When multiplying $$0.245 	imes 36.74 / 200.0$$, the calculator gives $$0.045007. $$How should this be reported using the correct number of significant figures?

Accepted Answer

$$0.04501$$

Question 8

Convert $$67 mL to $$liters using the correct conversion factor.

Accepted Answer

$$0.067 L$$

Question 9

A rock has a mass of $$30 g $$and a volume of $$6.7 mL. $$What is its density in $$g/mL$$?

Accepted Answer

$$4.48$$ $$g/mL$$

Question 10

Which of the following best describes an isotope?

Accepted Answer

An atom with the same number of protons but a different number of neutrons.

Question 11

Chlorine has two main isotopes: $$^{35}Cl ($$mass $$= 34.97 u$$, abundance $$= 75.8\%) $$and $$^{37}Cl ($$mass $$= 36.97 u$$, abundance $$= 24.2\%). $$What is the average atomic mass of chlorine?

Accepted Answer

$$35.47 u$$

Question 12

How many atoms are present in $$4$$ moles of carbon? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$2.4 	imes 10$$^{24}$$ atoms

Question 13

What is the molar mass of $$H_2SO_4 ($$Sulfuric acid)? (H = 1.01 g/mol, S = 32.07 g/mol, O = 16.00 g/mol)

Accepted Answer

$$98.09 g/$$mol

Question 14

A neutral atom of copper ($$^{65}Cu) $$has how many protons, neutrons, and electrons?

Accepted Answer

29 protons, 36 neutrons, 29 electrons

Question 15

Which of the following is a homogeneous mixture?

Accepted Answer

Saltwater

Question 16

Which of the following is the correct formula for calculating density?

Accepted Answer

$$	ext{Density} = \frac{	ext{Mass}}{	ext{Volume}}$$

Question 17

Which of the following compounds is named correctly according to ionic compound naming rules?

Accepted Answer

NaCl: Sodium Chloride

Question 18

Which group in the periodic table contains the noble gases?

Accepted Answer

Group 18

Question 19

A cation is formed when an atom:

Accepted Answer

Loses one or more electrons

Fundamental Concepts in Measurement: Accuracy, Precision, and Significant Figures

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