$23.9^\circ\\mathrm{C}, 297.0\\mathrm{K}$

Question 1

Which of the following best describes a scientific theory?

Accepted Answer

A well-substantiated explanation of some aspect of the natural world that can incorporate laws, hypotheses, and facts.

Question 2

A student measures the mass of a metal sample as 176 g and its volume as 20.0 cm³. What is the density of the metal?

Accepted Answer

$8.80 \mathrm{g/cm^3}$

Question 3

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

Accepted Answer

Burning wood

Question 4

A compound has an empirical formula of CH$_2$O and a molar mass of 180.16 g/mol. What is its molecular formula?

Accepted Answer

$\mathrm{C_6H_{12}O_6}$

Question 5

Which of the following is an intensive property of matter?

Accepted Answer

Density

Question 6

Convert a temperature of 75 $^\circ$F to Celsius and Kelvin. ($^\circ$C = ($^\circ$F - 32) $	imes$ 5/9; K = $^\circ$C + 273.15)

Accepted Answer

$23.9^\circ\mathrm{C}, 297.0\mathrm{K}$

Question 7

Which of the following best describes the difference between a scientific law and a scientific theory?

Accepted Answer

A law summarizes what happens, while a theory is a model that explains why it happens.

Question 8

How many significant figures are in the measurement 0.0780 g?

Accepted Answer

4

Question 9

Which of the following compounds is ionic?

Accepted Answer

$\mathrm{FeCl_3}$

Question 10

A chemical reaction releases heat into the surroundings. Is this reaction endothermic or exothermic?

Accepted Answer

Exothermic

Question 11

Which of the following is a homogeneous mixture?

Accepted Answer

Salt water

Question 12

Calculate the formula mass of aluminum sulfate, $\mathrm{Al_2(SO_4)_3}$.

Accepted Answer

$342.3\mathrm{amu}$

Question 13

A student has a mass of 150 lb. What is this mass in kilograms? ($1\mathrm{kg} = 2.205\mathrm{lb}$)

Accepted Answer

$68.0\mathrm{kg}$

Question 14

Which of the following statements about the conservation of mass is correct?

Accepted Answer

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

Question 15

Which of the following is the correct order of steps in the scientific method?

Accepted Answer

Observation, Hypothesis, Experiment, Theory

Question 16

How many protons and electrons does an atom with atomic number 23 have?

Accepted Answer

23 protons, 23 electrons

Question 17

Which of the following is a physical property?

Accepted Answer

Density

Question 18

What is the charge on the chromium ion in the compound $\mathrm{Cr_2O_3}$?

Accepted Answer

$+3$

Question 19

Which of the following best describes the difference between an empirical formula and a molecular formula?

Accepted Answer

An empirical formula shows the simplest whole-number ratio of atoms, while a molecular formula shows the actual number of atoms in a molecule.

Question 20

A scientist observes that a certain reaction always produces 5 grams of product. Is this observation a hypothesis, a law, or a theory?

Accepted Answer

Law

General Chemistry I: Core Concepts and Problem Solving

Study Guide - Practice Questions