$$1.2044 \times 10$$^{24}$$ molecules

Question 1

Which of the following statements best describes the difference between a chemical change and a physical change?

Accepted Answer

A chemical change results in the formation of one or more new substances, while a physical change does not alter the chemical composition.

Question 2

Which of the following is an example of an intensive property?

Accepted Answer

Density

Question 3

Convert 470 nanometers (nm) to meters (m).

Accepted Answer

$$4.7 	imes 10$$^{-7}$$ m

Question 4

Which of the following best describes Avogadro’s number?

Accepted Answer

The number of particles (atoms, molecules, ions) in one mole of a substance.

Question 5

A sample contains 2.0 moles of $$\mathrm{CO_2$}. $$How many molecules of $$\mathrm{CO_2$}$$ are present?

Accepted Answer

$$1.2044 	imes 10$$^{24}$$ molecules

Question 6

Which of the following compounds is an example of a molecular compound?

Accepted Answer

$$\mathrm{$$CCl_4$$}$$

Question 7

What is the empirical formula for a compound with the molecular formula $$\mathrm{C_6H_{12}O_6$}$$?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 8

A neutral atom of sodium ($$\mathrm{Na}) $$has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

12

Question 9

Which of the following ions is a cation?

Accepted Answer

$$\mathrm{Na^+}$$

Question 10

What is the correct name for $$\mathrm{N_2O_5}$$?

Accepted Answer

Dinitrogen pentoxide

Question 11

Balance the following equation: $$\mathrm{C_3H_8 + O_2$ \rightarrow CO_2$ + H_2O}$$

Accepted Answer

$$\mathrm{C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O}$$

Question 12

Which of the following is the correct formula for calcium nitrate?

Accepted Answer

$$\mathrm{Ca(NO_3$)_2}$$

Question 13

A reaction has a theoretical yield of 10.0 g and an actual yield of 8.0 g. What is the percent yield?

Accepted Answer

$$80\%$$

Question 14

Which of the following is a correct statement about isotopes?

Accepted Answer

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

Question 15

Which of the following is the correct formula for the compound formed between aluminum and oxygen?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 16

If 25.0 g of $$\mathrm{H_2O}$$ contains how many moles of water? (Molar mass of $$\mathrm{H_2O} = 18.0 g/$$mol)

Accepted Answer

$$1.39$$ mol

Question 17

Which of the following best describes the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 18

Which of the following is the correct name for $$\mathrm{$$PCl_3$$}$$?

Accepted Answer

Phosphorus trichloride

Question 19

A sample of $$\mathrm{Na_2SO_4}$$ contains 0.50 mol. How many formula units are present?

Accepted Answer

$$3.01 	imes 10$$^{23}$$

Question 20

Which of the following is a heterogeneous mixture?

Accepted Answer

Sand and iron filings

General Chemistry Exam 1 Study Guide: Matter, Atoms, Molecules, and Chemical Reactions

Study Guide - Practice Questions