ATI Chemistry Practice Test 3

Question 1

What is the pH of a solution with a hydrogen ion concentration [H+] of 1 x 10^-4 M?

Accepted Answer

4

Answer

pH = -log[H+] = -log(1 x 10^-4) = 4. This solution is acidic since the pH is below 7.

Question 2

Which type of chemical bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Answer

Covalent bonds form when atoms share one or more pairs of electrons, typically occurring between nonmetal elements.

Question 3

In an exothermic reaction, what happens to energy?

Accepted Answer

Energy is released to the surroundings

Answer

Exothermic reactions release energy (usually as heat) to the surroundings, resulting in a negative enthalpy change (ΔH < 0).

Question 4

What is the molarity of a solution containing 58.5 grams of NaCl dissolved in enough water to make 2 liters of solution? (Molar mass of NaCl = 58.5 g/mol)

Accepted Answer

0.5 M

Answer

Molarity = moles of solute / liters of solution. Moles of NaCl = 58.5g / 58.5g/mol = 1 mol. Molarity = 1 mol / 2 L = 0.5 M.

Question 5

Which of the following is a property of a buffer solution?

Accepted Answer

It resists changes in pH when small amounts of acid or base are added

Answer

Buffer solutions resist pH changes when small amounts of acid or base are added, maintaining pH within a narrow range.

HESI (ATI) Practice Test

HESI (ATI) Practice Test

ATI Chemistry Practice Test 3