$$1.20 \times 10$$^{24}$$ atoms

Question 1

Which of the following is a chemical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

Which of the following correctly expresses the relationship between Celsius and Kelvin temperatures?

Accepted Answer

$$K = ^\circ C + 273$$

Question 3

A sample of gold has a mass of 38.6 g and a volume of 2.00 cm$$^3. $$What is its density?

Accepted Answer

$$19.3\ \mathrm{g/cm}^3$$

Question 4

Which of the following statements about subatomic particles is correct?

Accepted Answer

Electrons are negatively charged and found outside the nucleus.

Question 5

Which of the following is the correct symbol for the element with atomic number 17?

Accepted Answer

Cl

Question 6

A student measures the mass of a sample as 12.30 g and its volume as 4.0 mL. How many significant figures should the calculated density have?

Accepted Answer

2

Question 7

Which of the following is a physical property?

Accepted Answer

Density

Question 8

Convert 98.6 $$^\circF ($$normal human body temperature) to Celsius. Use the formula $$^\circ C = ( ^\circ F - 32 ) 	imes \frac{5}{9}.$$

Accepted Answer

$$37.0\ ^\circ C$$

Question 9

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

Accepted Answer

kilogram (kg)

Question 10

How many atoms are in 2.00 moles of magnesium ($$\mathrm{Mg}$$)? ($$1\ 	ext{mol} = 6.022 	imes 10$$^{23}$$ atoms)

Accepted Answer

$$1.20 	imes 10$$^{24}$$ atoms

Question 11

Which of the following ions is correctly matched with its charge?

Accepted Answer

$$\mathrm{Na}^+$$

Question 12

A naturally occurring element has two isotopes: 70.0% with mass 62.93 amu and 30.0% with mass 64.93 amu. What is the average atomic mass?

Accepted Answer

$$63.53\ \mathrm{amu}$$

Question 13

Which of the following best describes the modern atomic theory?

Accepted Answer

Atoms are composed of protons, neutrons, and electrons.

Question 14

Which element is located in period 3, group 2 of the periodic table?

Accepted Answer

Magnesium (Mg)

Question 15

What is the molar mass of $$\mathrm{CO}_2$$?

Accepted Answer

$$44.01\ \mathrm{g/mol}$$

Question 16

A patient receives 250 mg of a medication. How many grams is this? ($$1\ \mathrm{g} = 1000\ \mathrm{mg})$$

Accepted Answer

$$0.250\ \mathrm{g}$$

Question 17

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

Accepted Answer

Boiling water to produce steam

Question 18

How many significant figures are in the measurement 0.004560 g?

Accepted Answer

4

Question 19

A compound contains 2.00 moles of hydrogen atoms. How many grams of hydrogen does it contain? ($$1\ 	ext{mol H} = 1.008\ \mathrm{g})$$

Accepted Answer

$$2.02\ \mathrm{g}$$

Question 20

Which of the following best describes the difference between a period and a group on the periodic table?

Accepted Answer

A period is a horizontal row; a group is a vertical column.

General Chemistry Exam 1 Study Guide: Matter, Measurement, and Atomic Theory

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