Q: Convert 0.025 kg to milligrams ($$\mathrm{mg}).$$

$$0.025\ \mathrm{kg} \times \frac{1000\ \mathrm{g}}{1\ \mathrm{kg}} \times \frac{1000\ \mathrm{mg}}{1\ \mathrm{g}} = 25,000\ \mathrm{mg}$$

Q: A food contains 9 g of fat, 4 g of protein, and 12 g of carbohydrate. If fat provides $$37\ \mathrm{kJ/g}$$, protein $$17\ \mathrm{kJ/g}$$, and carbohydrate $$17\ \mathrm{kJ/g}$$, what is the total energy content of the food?

$$(9 \times 37) + (4 \times 17) + (12 \times 17) = 333\ \mathrm{kJ}$$

Q: A solution contains 0.50 g of NaCl in 100 g of water. What is the percentage of NaCl in the solution?

$$\frac{0.50}{100} \times 100\% = 0.5\%$$

Question 1

Which of the following is an example of a chemical change?

Accepted Answer

Iron rusting in moist air

Question 2

A student measures the mass of a sample as 12.30 g and its volume as 4.1 mL. What is the density of the sample, reported with the correct number of significant figures?

Accepted Answer

$$\frac{12.30}{4.1} = 3.0\ \mathrm{g/mL}$$

Question 3

Which of the following statements about the scientific method is correct?

Accepted Answer

An experiment is designed to test a hypothesis.

Question 4

Convert 0.025 kg to milligrams ($$\mathrm{mg}).$$

Accepted Answer

$$0.025\ \mathrm{kg} 	imes \frac{1000\ \mathrm{g}}{1\ \mathrm{kg}} 	imes \frac{1000\ \mathrm{mg}}{1\ \mathrm{g}} = 25,000\ \mathrm{mg}$$

Question 5

Which element is a metalloid found in period 3 of the periodic table?

Accepted Answer

Silicon (Si)

Question 6

A food contains 9 g of fat, 4 g of protein, and 12 g of carbohydrate. If fat provides $$37\ \mathrm{kJ/g}$$, protein $$17\ \mathrm{kJ/g}$$, and carbohydrate $$17\ \mathrm{kJ/g}$$, what is the total energy content of the food?

Accepted Answer

$$(9 	imes 37) + (4 	imes 17) + (12 	imes 17) = 333\ \mathrm{kJ}$$

Question 7

Which of the following is the correct scientific notation for 0.00056?

Accepted Answer

$$5.6 	imes 10$$^{-4}$$

Question 8

A radioactive isotope has a half-life of 3 hours. If you start with 80 mg, how much remains after 9 hours?

Accepted Answer

$$80\ \mathrm{mg} \rightarrow 40\ \mathrm{mg} \rightarrow 20\ \mathrm{mg} \rightarrow 10\ \mathrm{mg}$$

Question 9

Which of the following is the correct electron arrangement for phosphorus (atomic number 15)?

Accepted Answer

2, 8, 5

Question 10

Which of the following is a correct balanced nuclear equation for the beta decay of carbon-14?

Accepted Answer

$$^{14}_{6}\mathrm{C} \$$rightarrow ^{14}$$_{7}\mathrm{N} $$+ ^{0}$$_{-1}\beta$$

Question 11

Which of the following statements about isotopes is true?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 12

A sample of gold has an atomic number of 79 and a mass number of 197. How many neutrons does it contain?

Accepted Answer

$$197 - 79 = 118$$ neutrons

Question 13

Which group on the periodic table contains the noble gases?

Accepted Answer

Group 18 (8A)

Question 14

A patient’s temperature is measured as $$102.2\ ^\circ\mathrm{F}. $$What is this temperature in Celsius?

Accepted Answer

$$T_C = \frac{102.2 - 32}{1.8} = 39.0\ ^\circ\mathrm{C}$$

Question 15

Which of the following is a physical property of mercury?

Accepted Answer

It is liquid at room temperature.

Question 16

Which of the following best describes a homogeneous mixture?

Accepted Answer

Salt water

Question 17

A solution contains 0.50 g of NaCl in 100 g of water. What is the percentage of NaCl in the solution?

Accepted Answer

$$\frac{0.50}{100} 	imes 100\% = 0.5\%$$

Question 18

Which of the following particles has no charge and is found in the nucleus of an atom?

Accepted Answer

Neutron

Question 19

A 250 g sample of water is heated from $$20.0\ ^\circ\mathrm{C} to$$ $$35.0\ ^\circ\mathrm{C}. If $$the specific heat of water is $$4.184\ \mathrm{J/g}^\circ\mathrm{C}$$, how much heat is absorbed?

Accepted Answer

$$q = 250 	imes 4.184 	imes (35.0 - 20.0) = 15,690\ \mathrm{J}$$

CHE103 Exam 1 Study Guide: Chapters 1-5 (Chemistry in Our Lives, Measurements, Matter & Energy, Atoms & Elements, Nuclear Chemistry)

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