$1.81 \times 10^{24}$ molecules

Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically bonded in fixed proportions.

Question 2

Which statement about Dalton’s Atomic Theory is correct?

Accepted Answer

All atoms of a given element are identical in mass and properties.

Question 3

A sample contains 3.00 moles of water ($\mathrm{H_2O}$). How many molecules of water are present in the sample?

Accepted Answer

$1.81 	imes 10^{24}$ molecules

Question 4

Which of the following is a physical change?

Accepted Answer

Melting of ice.

Question 5

What is the chemical formula for ammonium sulfate?

Accepted Answer

$\mathrm{(NH_4)_2SO_4}$

Question 6

Which of the following is the correct balanced equation for the combustion of methane ($\mathrm{CH_4}$)?

Accepted Answer

$\mathrm{CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O}$

Question 7

Which of the following ions is isoelectronic with neon ($\mathrm{Ne}$)?

Accepted Answer

$\mathrm{F^-}$

Question 8

A student measures the mass of a sample as 2.50 g and its volume as 1.00 mL. What is the density of the sample?

Accepted Answer

$2.50 \mathrm{~g/mL}$

Question 9

Which of the following is NOT a correct use of significant figures?

Accepted Answer

Reporting 100 as having three significant figures.

Question 10

Which statement best describes the difference between a mixture and a compound?

Accepted Answer

Mixtures can be separated by physical means, while compounds require chemical means.

Question 11

Which of the following is the correct formula weight (molar mass) of calcium nitrate ($\mathrm{Ca(NO_3)_2}$)?

Accepted Answer

$164 \mathrm{~g/mol}$

Question 12

Which of the following best describes Rutherford’s model of the atom?

Accepted Answer

Atoms consist of a dense nucleus containing protons and neutrons, with electrons orbiting around it.

Question 13

Which of the following is a binary compound?

Accepted Answer

$\mathrm{NaCl}$

Question 14

If you have 0.50 moles of $\mathrm{CO_2}$, how many grams do you have? ($\mathrm{Molar~mass~of~CO_2 = 44~g/mol}$)

Accepted Answer

$22~\mathrm{g}$

Question 15

Which of the following is a correct conversion between Celsius and Kelvin?

Accepted Answer

$K = ^\circ C + 273$

Question 16

Which of the following is a correct chemical formula for a common acid?

Accepted Answer

$\mathrm{HCl}$

Question 17

Which of the following is a correct statement about isotopes?

Accepted Answer

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

Question 18

A chemical reaction is represented as $\mathrm{2H_2 + O_2 \rightarrow 2H_2O}$. How many moles of water are produced from 4 moles of hydrogen gas?

Accepted Answer

4 moles

Question 19

Which of the following is a correct use of scientific notation?

Accepted Answer

$0.00056 = 5.6 	imes 10^{-4}$

Question 20

Which of the following is a correct statement about the periodic table?

Accepted Answer

Elements in the same group have similar chemical properties.

General Chemistry Exam Study Guide: Matter, Atomic Structure, and Chemical Reactions

Study Guide - Practice Questions