$$3.0 \times 10$$^{-3}$$\ \mathrm{mol/L}$$

Question 1

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

Accepted Answer

Melting ice into liquid water

Question 2

A sample of water has a mass of 25.0 g and occupies a volume of 25.0 mL. What is the density of water in this sample?

Accepted Answer

$$\frac{25.0\ \mathrm{g}}{25.0\ \mathrm{mL}} = 1.00\ \mathrm{g/mL}$$

Question 3

Which of the following statements about isotopes is TRUE?

Accepted Answer

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

Question 4

A radioactive isotope has a half-life of 10 years. If you start with 80 g, how much remains after 30 years?

Accepted Answer

20 g

Question 5

Which of the following is a correct scientific notation for the number 0.000012?

Accepted Answer

$$1.2 	imes 10$$^{-5}$$

Question 6

Which of the following is a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Question 7

What is the correct symbol for the element calcium?

Accepted Answer

Ca

Question 8

Which of the following best describes a chemical reaction?

Accepted Answer

A process that results in the formation of new substances with different chemical properties

Question 9

How many significant figures are in the measurement 0.00250 g?

Accepted Answer

3

Question 10

Which of the following is the correct conversion factor to convert 1 inch to centimeters?

Accepted Answer

$$1\ \mathrm{in.} = 2.54\ \mathrm{cm}$$

Question 11

Which of the following is a correct statement about the law of conservation of energy?

Accepted Answer

Energy is neither created nor destroyed, only transformed.

Question 12

A sample of carbon-14 has a half-life of 5730 years. If only 12.5% of the original sample remains, how many half-lives have passed?

Accepted Answer

3

Question 13

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

Accepted Answer

Neutron

Question 14

Which of the following is the correct formula for calculating specific heat?

Accepted Answer

$$\mathrm{Specific\ Heat} = \frac{\mathrm{heat}}{\mathrm{grams} 	imes \Delta T}$$

Question 15

Which of the following is a correct statement about noble gases?

Accepted Answer

They are unreactive because they have a full valence shell.

Question 16

Which of the following is the correct SI unit for energy?

Accepted Answer

joule (J)

Question 17

Which of the following best describes an alpha particle?

Accepted Answer

A positively charged particle consisting of two protons and two neutrons

Question 18

If a solution contains 1.5 x $$10^{-3}$$ mol of solute in 500 mL of water, what is the molarity of the solution?

Accepted Answer

$$3.0 	imes 10$$^{-3}$$\ \mathrm{mol/L}$$

Question 19

Which of the following ions is named using Roman numerals to indicate its charge?

Accepted Answer

Fe$$^{2+}$$

Question 20

Which of the following is a polyatomic ion?

Accepted Answer

NH$$_4$$^{+}$$

GOB Chemistry Study Notes: Matter, Measurement, Radioactivity, and How Elements Combine

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