ATI - HESI Chemistry Practice Test 1

Question 1

If 0.5 moles of NaCl are dissolved in 2.0 liters of water, what is the molarity of the solution?

Accepted Answer

0.25 M

Answer

Molarity (M) = moles of solute ÷ liters of solution. 0.5 mol ÷ 2.0 L = 0.25 M.

Question 2

Which type of chemical bond is formed when two nonmetal atoms share electrons equally?

Accepted Answer

Nonpolar covalent bond

Answer

A nonpolar covalent bond forms when electrons are shared equally between two atoms of the same or similar electronegativity, as seen in molecules like O₂ or N₂.

Question 3

How many valence electrons does an oxygen atom (atomic number 8) have?

Accepted Answer

6

Answer

Oxygen has the electron configuration 2, 6 — meaning 2 electrons in the first shell and 6 in the second (valence) shell.

Question 4

When hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) in a neutralization reaction, what are the products?

Accepted Answer

NaCl and H₂O

Answer

Acid–base neutralization produces a salt and water. HCl + NaOH → NaCl (salt) + H₂O.

Question 5

Two atoms of the same element that have the same number of protons but different numbers of neutrons are called:

Accepted Answer

Isotopes

Answer

Isotopes are atoms of the same element (same atomic number/protons) that differ in their number of neutrons, giving them different mass numbers.

HESI (ATI) Practice Test

HESI (ATI) Practice Test

ATI - HESI Chemistry Practice Test 1