$$0.5\ \mathrm{mg/kg} \times 70\ \mathrm{kg} = 35\ \mathrm{mg}$$

Question 1

Which of the following numbers has the correct number of significant figures according to the zero rules: 0.00450?

Accepted Answer

3 significant figures

Question 2

A sample of water has a mass of 18.0 g and a volume of 18.0 mL. What is its density?

Accepted Answer

$$\frac{18.0\ \mathrm{g}}{18.0\ \mathrm{mL}} = 1.00\ \mathrm{g/mL}$$

Question 3

Which of the following is a chemical change?

Accepted Answer

Burning wood

Question 4

Convert 25.0 °C to Kelvin.

Accepted Answer

$$25.0 + 273.15 = 298.15\ \mathrm{K}$$

Question 5

Which of the following is a heterogeneous mixture?

Accepted Answer

Oil and water

Question 6

What is the molar mass of NaCl?

Accepted Answer

$$22.99\ \mathrm{g/mol} + 35.45\ \mathrm{g/mol} = 58.44\ \mathrm{g/mol}$$

Question 7

Which of the following compounds is ionic?

Accepted Answer

NaCl

Question 8

How many valence electrons does oxygen have?

Accepted Answer

6

Question 9

Which particle is emitted during beta decay?

Accepted Answer

An electron

Question 10

What is the molecular shape of CO$$_2$$ according to its Lewis structure?

Accepted Answer

Linear

Question 11

Which of the following molecules is polar?

Accepted Answer

H$$_2O$$

Question 12

A radioactive isotope has a half-life of 4 hours. How much of a 100 g sample remains after 12 hours?

Accepted Answer

12.5 g

Question 13

Balance the following chemical equation: $$\mathrm{N_2$} + \mathrm{H_2$} \rightarrow \mathrm{NH_3$}$$

Accepted Answer

$$\mathrm{N_2$} + 3\mathrm{H_2$} \rightarrow 2\mathrm{NH_3$}$$

Question 14

How many moles are in 36.0 g of water ($$\mathrm{H_2O}$$)? (Molar mass of $$\mathrm{H_2O} is 18.0 g/$$mol)

Accepted Answer

$$\frac{36.0\ \mathrm{g}}{18.0\ \mathrm{g/mol}} = 2.00\ \mathrm{mol}$$

Question 15

Which of the following is a pure element?

Accepted Answer

Copper (Cu)

Question 16

What is the specific gravity of a substance with a density of $$2.50\ \mathrm{g/mL}$$? (Density of water is $$1.00\ \mathrm{g/mL})$$

Accepted Answer

$$\frac{2.50}{1.00} = 2.50$$

Question 17

Which of the following is the correct name for the compound $$\mathrm{P_2O_5}$$?

Accepted Answer

Diphosphorus pentoxide

Question 18

How many protons, neutrons, and electrons are in $$^{14}\mathrm{C}$$?

Accepted Answer

6 protons, 8 neutrons, 6 electrons

Question 19

Which of the following is a covalent compound?

Accepted Answer

CO$$_2$$

Question 20

A medication is prescribed at a dosage of 0.5 mg/kg for a patient weighing 70 kg. What is the total dose in milligrams?

Accepted Answer

$$0.5\ \mathrm{mg/kg} 	imes 70\ \mathrm{kg} = 35\ \mathrm{mg}$$

GOB Chemistry Exam 1 Study Guide: Key Concepts and Applications

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