Question 1

Which of the following elements is classified as a noble gas on the periodic table?

Accepted Answer

Argon

Question 2

A student measures the mass of a sample as 12.34 g using a balance with an uncertainty of ±0.01 g. Which of the following best represents the measurement with its significant figures?

Accepted Answer

$$12.34 \pm 0.01 g$$

Question 3

Which of the following is the correct electron configuration for a neutral sodium atom ($$Z=11$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^1$$

Question 4

A solution contains 5.0 g of NaCl dissolved in 100 mL of water. What is the percentage by mass of NaCl in the solution?

Accepted Answer

$$4.8\%$$

Question 5

Which of the following best describes the difference between atomic number and atomic mass?

Accepted Answer

Atomic number is the number of protons; atomic mass is the sum of protons and neutrons.

Question 6

Which of the following ions has the electron configuration of a noble gas?

Accepted Answer

$$Na^+$$

Question 7

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

Accepted Answer

$$Ca_3$$($$PO_4)_2$

Question 8

Which of the following acids is correctly matched with its formula?

Accepted Answer

Nitric acid: $$HNO_3$$

Question 9

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two atoms.

Question 10

Which of the following molecules is a diatomic molecule that exists naturally?

Accepted Answer

$$O_2$$

Question 11

A radioactive isotope undergoes beta emission. What happens to its atomic number and mass number?

Accepted Answer

Atomic number increases by 1; mass number remains unchanged.

Question 12

Which of the following is the correct Lewis structure for water ($$H_2O$$)?

Accepted Answer

O atom with two single bonds to H atoms and two lone pairs on O.

Question 13

A student uses a graduated cylinder to measure the volume of a liquid and records 25.0 mL. The true volume is 24.8 mL. What is the percent error?

Accepted Answer

$$0.81\%$$

Question 14

Which of the following best describes the difference between a molecule and an ion?

Accepted Answer

A molecule is a group of atoms bonded together with no net charge; an ion is an atom or group of atoms with a net charge.

Question 15

Which of the following is the correct formula for the polyatomic ion sulfate?

Accepted Answer

$$SO_4$$^{2-}$$

Question 16

A sample contains 2.0 moles of carbon atoms. What is the mass of the sample? (Atomic mass of C = 12.01 g/mol)

Accepted Answer

$$24.02 g$$

Question 17

Which of the following best describes the color observed in a spectrophotometry experiment?

Accepted Answer

The color observed is the color transmitted by the solution.

Question 18

Which of the following is the correct name for $$Fe_2O_3$$?

Accepted Answer

Iron(III) oxide

Question 19

Which of the following best describes the process of volume by displacement?

Accepted Answer

Determining the volume of an object by the amount of liquid it displaces.

Question 20

Which of the following is the correct symbol for the isotope of carbon with 6 protons and 8 neutrons?

Accepted Answer

$$^{13}C$$

GOB Chemistry: Foundational Concepts and Laboratory Skills

Guida di studio - Domande di pratica

Study guide - Flashcard