Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

A sample of air can be separated into its components (oxygen, nitrogen, etc.) by physical means. Based on this, air is best classified as:

Accepted Answer

A homogeneous mixture

Question 3

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

Accepted Answer

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

Question 4

Which of the following is NOT a physical property?

Accepted Answer

Flammability

Question 5

A student is given a sample of an unknown element. It is shiny, conducts electricity, and is malleable. Based on these properties, the element is most likely:

Accepted Answer

A metal

Question 6

Which of the following best describes the difference between potential and kinetic energy?

Accepted Answer

Kinetic energy is energy of motion; potential energy is stored energy.

Question 7

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

Accepted Answer

Cl

Question 8

How many protons, neutrons, and electrons are present in a neutral atom of $$^{23}_{11}\mathrm{Na}$$?

Accepted Answer

11 protons, 12 neutrons, 11 electrons

Question 9

Which of the following best explains why metals are good conductors of electricity?

Accepted Answer

Metals have loosely held valence electrons that can move freely.

Question 10

Which of the following is the correct electron configuration for a neutral atom of oxygen ($$Z=8$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$

Question 11

A compound contains 2 atoms of hydrogen and 1 atom of oxygen. What is the chemical formula for this compound?

Accepted Answer

$$\mathrm{H}_2\mathrm{O}$$

Question 12

Which of the following statements about the Bohr model of the atom is correct?

Accepted Answer

Electrons move in fixed orbits around the nucleus.

Question 13

Which of the following best describes the relationship between wavelength ($$\lambda) $$and frequency ($$
u) of $$light?

Accepted Answer

As wavelength increases, frequency decreases.

Question 14

A student is asked to classify the following change: burning wood in a campfire. Which type of change is this?

Accepted Answer

Chemical change

Question 15

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 16

Which of the following best describes the energy change when a ball is dropped from a height?

Accepted Answer

Potential energy is converted to kinetic energy as the ball falls.

Question 17

Which of the following is the correct order of the visible spectrum from lowest to highest energy?

Accepted Answer

Red, orange, yellow, green, blue, violet

Question 18

A sample contains 3.0 moles of carbon atoms. How many atoms are present in the sample? (Use Avogadro's number: $$6.02 	imes 10$$^{23}$$ atoms/mol)

Accepted Answer

$$1.81 	imes 10$$^{24}$$ atoms

Question 19

Which of the following is the correct maximum number of electrons that can occupy the $$2p$$ sublevel?

Accepted Answer

6

Question 20

Which of the following is a correct application of the law of definite composition?

Accepted Answer

A sample of water always contains hydrogen and oxygen in a 2:1 ratio by number of atoms.

Introduction to Chemistry: Key Concepts and Learning Objectives

Guida di studio - Domande di pratica

Study guide - Flashcard