WGU D425 Introduction to Chemistry -PA and OA ACTUAL EXAM(2026) 100%VERIFIED |complete QUESTIONS AND ANSWERS | GRADED A+.

WGU D425 Introduction to Chemistry -PA and OA ACTUAL EXAM(2026)
100%VERIFIED |complete QUESTIONS AND ANSWERS | GRADED A+.

1. Describe why the gram is preferred as a mass unit in laboratory settings.

The gram is preferred because it is a convenient unit for measuring
small quantities of substances in chemical experiments.

The gram is preferred due to its equivalence to the kilogram in all
calculations.

The gram is chosen because it is the largest unit of mass available.

The gram is used because it is the only unit recognized by
international standards.

2. If a molecule has a tetrahedral geometry and one of the atoms is replaced by
a lone pair of electrons, what will be the new bond angle in the resulting
trigonal pyramidal shape?

Less than 109.5 degrees

Exactly 109.5 degrees

Exactly 120 degrees

Greater than 109.5 degrees

3. What is the common name for the molecule with the formula SO3?

Sulfate

Sulfur dioxide

Sulfuric acid

Sulfur trioxide

,4. Describe how percent composition by mass is useful in determining the
composition of a chemical compound.

Percent composition by mass is used solely for balancing chemical
equations.

Percent composition by mass is only useful for calculating the total
mass of a compound.

Percent composition by mass provides no useful information about
the elements in a compound.

Percent composition by mass helps identify the proportion of each
element in a compound, which is essential for understanding its
chemical behavior and reactivity.

5. What subatomic particles are found in a neutral atom with an atomic number
greater than two?

Only neutrons and electrons.

Only protons and electrons.

Protons and neutrons in the nucleus, with electrons surrounding the
nucleus.

Protons, neutrons, and positrons.

6. Which reaction shows a redox reaction?

CaO + 2HCl → CaCl2 + H2O

NaOH + HCl → NaCl + H2O

H2 + Cl2 → 2HCl

CaCO3 → CaO + CO

,7. In the decomposition reaction of hydrogen peroxide, what is the balanced
equation?

2H2O2 -> O2 + 2H2O

H2O2 + H2O -> O2 + 2H2

2H2O2 -> 2H2 + O2

H2O2 -> H2 + O2

8. If you have 7.0 lb of titanium, what would be the volume in cubic inches, using
the density of titanium?

Volume = 15.5 in³

Volume = 25.0 inr

Volume = 20.0 inr

Volume = 10.0 inr

9. What is the common name for the acid represented by the formula HF(aq)?

Nitric acid

Hydrochloric acid

Sulfuric acid

Hydrofluoric acid

10. The percentage by mass of a compound by each of its elements is known as
its:

Mole

Percent composition

Mass unit

, Formula mass

11. Describe the process of balancing the chemical equation Pb(OH)4 + H2SO4
-> ?

Balancing is unnecessary if the equation is already partially correct.

To balance the equation, identify the number of each type of atom
on both sides and adjust coefficients to ensure they are equal.

Balancing involves only adjusting the reactants without changing the
products.

Balancing requires adding more reactants than products.

12. Describe what it means for an element to be diatomic and provide
examples.

A diatomic element can only be a metal; examples include Sodium
and Calcium.

A diatomic element consists of two atoms bonded together;
examples include Nitrogen and Fluorine.

A diatomic element is one that exists as a single atom; examples
include Carbon and Sodium.

A diatomic element is one that forms compounds with three atoms;
examples include Oxygen and Hydrogen.

13. If a different substance has a mass of 100g and a density of 5g/mL, what
would be the volume of this substance?

20 mL

5 mL

25 mL