Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically combined in a fixed ratio

Question 2

Which of the following is a homogeneous mixture?

Accepted Answer

Sugar dissolved in water

Question 3

Which statement about significant figures is correct?

Accepted Answer

Zeros at the end of a number with a decimal point are significant

Question 4

A sample of water has a mass of 25.0 g and a volume of 25.0 mL. What is its density?

Accepted Answer

$$d = \frac{25.0\,g}{25.0\,mL} = 1.00\,g/mL$$

Question 5

Which of the following is a physical change?

Accepted Answer

Melting of ice

Question 6

What is the correct formula to convert Fahrenheit to Celsius?

Accepted Answer

$$^\circ C = \frac{(^\circ F - 32)}{1.8}$$

Question 7

Which of the following statements about energy is TRUE?

Accepted Answer

Energy takes various forms, but is never created or destroyed

Question 8

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 9

Which form of radiation has no charge and the greatest ability to penetrate tissue?

Accepted Answer

Gamma ray

Question 10

Which of the following is NOT a unit for measuring radioactivity?

Accepted Answer

Joule (J)

Question 11

Which of the following best describes the difference between accuracy and precision?

Accepted Answer

Accuracy is how close measurements are to the true value; precision is how close measurements are to each other

Question 12

Which of the following is a correct statement about the conservation of matter?

Accepted Answer

Matter is neither created nor destroyed in chemical reactions

Question 13

A sample contains 0.0031 kg. How many significant figures does this measurement have?

Accepted Answer

4

Question 14

Which of the following is the correct SI prefix for $$10^{-6}$$?

Accepted Answer

micro

Question 15

Which of the following elements is a metalloid?

Accepted Answer

Boron (B)

Question 16

Which of the following is the correct formula for density?

Accepted Answer

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

Question 17

Which of the following is a chemical change?

Accepted Answer

Burning gasoline in a car engine

Question 18

A nutritional Calorie (Cal) is equal to how many calories?

Accepted Answer

1000

Question 19

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 20

Which of the following radioisotopes has the longest physical half-life?

Accepted Answer

Uranium-238

General Chemistry Basics: Matter, Measurement, and Radioactivity

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