WGU D425 Intro to Chemistry Objective
Assessment Actual Exam 2026/2027 |
Questions with Verified Answers 100%
Correct | Pass Guaranteed | Grade A
Q01 Which of the following is the correct symbol for an atom with 11 protons, 12 neutrons, and
11 electrons?
Answer: ²³₁₁Na
Rationale: Sodium (Na) has atomic number 11 (protons = 11). Mass number = protons +
neutrons = 11 + 12 = 23.
Q02 How many significant figures are in the number 0.00520?
Answer: 3
Rationale: Leading zeros are not significant; trailing zeros after the decimal point are
significant. So 5, 2, and 0 are significant → 3 sig figs.
Q03 What is the correct name for the compound Fe₂(SO₄)₃?
Answer: Iron(III) sulfate
Rationale: Fe³⁺ is iron(III), SO₄²⁻ is sulfate. Roman numeral required because iron has multiple
oxidation states.
Q04 Which of the following elements has the highest electronegativity?
Answer: Fluorine
Rationale: Fluorine is the most electronegative element on the periodic table (value = 3.98).
, Q05 What is the electron configuration of the chloride ion (Cl⁻)?
Answer: [Ne] 3s² 3p⁶
Rationale: Neutral Cl is [Ne] 3s² 3p⁵. Gain of one electron fills the 3p subshell to 3p⁶ (noble gas
configuration).
Q06 Which bond type is present in HCl?
Answer: Polar covalent
Rationale: Electronegativity difference between H (2.2) and Cl (3.0) is 0.8 → polar covalent
(between 0.4 and 1.7).
Q07 How many moles of oxygen atoms are in 2.5 moles of CaCO₃?
Answer: 7.5 moles
Rationale: CaCO₃ contains 3 oxygen atoms per formula unit → 2.5 mol × 3 = 7.5 mol O atoms.
Q08 What is the molar mass of glucose (C₆H₁₂O₆)?
Answer: 180.18 g/mol
Rationale: 6×12.01 + 12×1.008 + 6×16.00 = 72.06 + 12.096 + 96.00 = 180.156 ≈ 180.18 g/mol.
Q09 Which law states that the volume of a gas is directly proportional to its temperature at
constant pressure?
Answer: Charles’s Law
Rationale: V₁/T₁ = V₂/T₂ (temperature in Kelvin).
Assessment Actual Exam 2026/2027 |
Questions with Verified Answers 100%
Correct | Pass Guaranteed | Grade A
Q01 Which of the following is the correct symbol for an atom with 11 protons, 12 neutrons, and
11 electrons?
Answer: ²³₁₁Na
Rationale: Sodium (Na) has atomic number 11 (protons = 11). Mass number = protons +
neutrons = 11 + 12 = 23.
Q02 How many significant figures are in the number 0.00520?
Answer: 3
Rationale: Leading zeros are not significant; trailing zeros after the decimal point are
significant. So 5, 2, and 0 are significant → 3 sig figs.
Q03 What is the correct name for the compound Fe₂(SO₄)₃?
Answer: Iron(III) sulfate
Rationale: Fe³⁺ is iron(III), SO₄²⁻ is sulfate. Roman numeral required because iron has multiple
oxidation states.
Q04 Which of the following elements has the highest electronegativity?
Answer: Fluorine
Rationale: Fluorine is the most electronegative element on the periodic table (value = 3.98).
, Q05 What is the electron configuration of the chloride ion (Cl⁻)?
Answer: [Ne] 3s² 3p⁶
Rationale: Neutral Cl is [Ne] 3s² 3p⁵. Gain of one electron fills the 3p subshell to 3p⁶ (noble gas
configuration).
Q06 Which bond type is present in HCl?
Answer: Polar covalent
Rationale: Electronegativity difference between H (2.2) and Cl (3.0) is 0.8 → polar covalent
(between 0.4 and 1.7).
Q07 How many moles of oxygen atoms are in 2.5 moles of CaCO₃?
Answer: 7.5 moles
Rationale: CaCO₃ contains 3 oxygen atoms per formula unit → 2.5 mol × 3 = 7.5 mol O atoms.
Q08 What is the molar mass of glucose (C₆H₁₂O₆)?
Answer: 180.18 g/mol
Rationale: 6×12.01 + 12×1.008 + 6×16.00 = 72.06 + 12.096 + 96.00 = 180.156 ≈ 180.18 g/mol.
Q09 Which law states that the volume of a gas is directly proportional to its temperature at
constant pressure?
Answer: Charles’s Law
Rationale: V₁/T₁ = V₂/T₂ (temperature in Kelvin).
