$$\frac{40.0}{100.0} \times 100\% = 40.0\%$$

$$2 \times 1.01\ \mathrm{g/mol} + 16.00\ \mathrm{g/mol} = 18.02\ \mathrm{g/mol}$$

$$\frac{3.01 \times 10$$^{23}$$}{6.022 \times 10$$^{23}$$} = 0.500\ \mathrm{mol}$$

Question 1

Which of the following best describes the difference between mass and weight?

Accepted Answer

Mass is the amount of matter in an object, while weight is the force exerted by gravity on that object.

Question 2

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

Accepted Answer

Burning wood in a campfire.

Question 3

A student mixes sand and salt in a beaker. Which type of mixture is formed?

Accepted Answer

Heterogeneous mixture

Question 4

Which of the following is a correct representation of the law of conservation of mass in a chemical reaction?

Accepted Answer

The total mass of reactants equals the total mass of products: $$\sum m_{reactants} = \sum m_{products}$$

Question 5

Which of the following is NOT a characteristic of science?

Accepted Answer

It is based on personal beliefs and opinions.

Question 6

A compound contains 40.0 g of carbon and 60.0 g of oxygen. What is the mass percent of carbon in the compound?

Accepted Answer

$$\frac{40.0}{100.0} 	imes 100\% = 40.0\%$$

Question 7

Which of the following is an example of applied research?

Accepted Answer

Developing a new drug to treat cancer.

Question 8

Which SI base unit is used to measure temperature?

Accepted Answer

Kelvin ($$K)$$

Question 9

A sample of gold has a mass of 19.3 g and a volume of 1.00 cm$$^3. $$What is the density of gold?

Accepted Answer

$$\frac{19.3\ \mathrm{g}}{1.00\ \mathrm{cm}^3} = 19.3\ \mathrm{g/cm}^3$$

Question 10

Which statement best describes Dalton’s atomic theory?

Accepted Answer

All matter is composed of indivisible atoms, and atoms of the same element are identical.

Question 11

What is the value of Avogadro’s number?

Accepted Answer

$$6.022 	imes 10$$^{23}$$

Question 12

A molecule of water ($$H_2O) $$has a molar mass of:

Accepted Answer

$$2 	imes 1.01\ \mathrm{g/mol} + 16.00\ \mathrm{g/mol} = 18.02\ \mathrm{g/mol}$$

Question 13

How many moles are present in $$3.01 	imes 10$$^{23}$$ molecules of CO_2$?

Accepted Answer

$$\frac{3.01 	imes 10$$^{23}$$}{6.022 	imes 10$$^{23}$$} = 0.500\ \mathrm{mol}$$

Question 14

Which of the following is an example of green chemistry?

Accepted Answer

Using renewable feedstocks to produce biodegradable plastics.

Question 15

Convert 0.250 moles of sodium ($$Na) to $$grams. (Atomic mass of $$Na = 22.99\ \mathrm{g/mol})$$

Accepted Answer

$$0.250\ \mathrm{mol} 	imes 22.99\ \mathrm{g/mol} = 5.75\ \mathrm{g}$$

Question 16

Which temperature scale is based on absolute zero?

Accepted Answer

Kelvin

Question 17

Which of the following best describes a hypothesis?

Accepted Answer

A tentative explanation that can be tested by experiments.

Question 18

A student has 12.0 g of $$C ($$carbon). How many moles of carbon does this represent? (Atomic mass of $$C = 12.01\ \mathrm{g/mol})$$

Accepted Answer

$$\frac{12.0\ \mathrm{g}}{12.01\ \mathrm{g/mol}} = 0.999\ \mathrm{mol}$$

Question 19

Which of the following is a correct example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Question 20

Which prefix and symbol represent $$10^{-3} in SI $$units?

Accepted Answer

Milli, $$m$$

Introductory Chemistry Exam 1 Study Guide – Step-by-Step Guidance

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