WGU D425 INTRODUCTION TO CHEMISTRY
OA FINAL TEST 2026 QUESTIONS WITH
CORRECT ANSWERS GRADED A+
• Miscible.
Answer: Two solvents that mix in any proportion to produce a solution (e.g.,
polar compounds in water).
• PO43-.
Answer: (Phosphate)
• What occurs in a decomposition reaction?.
Answer: one substance splits into two or more simpler substances
• Atomic Number.
Answer: Total number of protons in the nucleus.
• Density of an object? mass of 2.4019 and volume of 1.40mL
2.4019g/1.40mL=.
Answer: density = 1.7156g/mL= 1.72g/ml
• Percent Compostion by mass.
Answer: mass %= mass of element / mass of compound x 100
• what is the percent composition by mass for N in NH6PO4.
Answer: 12.18%
• Tetrahedral.
Answer: 109.5 degrees, 4 bonds
• how many moles of potassium chloride are required to yield 250g of oxygen
in the reaction 2KClO3 -> 2KCl+ 3O2.
Answer: 5.2 mol convert 250.0 grams to moles: moles=mass/ molar mass,
moles = 250.0/32= 7.81 mol molar ratio btwn KClO3 and O2 is 2:3 the 2=x
moles of KClO3 the 3 = 7.81 mol of O2 15.62=3x 15.62/3= x cross
multiplying to get 5.21 moles =# of moles of KClO3 req.
, • Inverse relationship.
Answer: One variable decreases when another variable increases.
• CO32-.
Answer: (Carbonate)
• Solubility Rules.
Answer: Guidelines determining solubility of compounds in water
• Solute.
Answer: Substance present in smaller amount (being dissolved).
• What does the term valence electrons refer to.
Answer: Electrons in the outer most shell.
• what is the correct formula of aluminum iodide.
Answer: Al3++3I− → AlI3
• what is the correct name for a molecule of SO3.
Answer: Sulfur trioxide
• if 14.67g of C2H6 is allowed to react with 39.51g of O2 as shown what
would be the limiting reactant molar mass (g/mole) C2H6= 30.08, O2=
31.998, H2O= 18.015, CO2= 44.08 2C2H6 + 7O2 -> 6H2O + 4CO2.
Answer: O2. in order to consume all the C2H6 we would need 54.62g of O2,
we only have 39.51g
• what role of the electrodes on pH meter.
Answer: they are dipped into the test solution to read the pH. the pH meter
has electrodes that are calibrated with solutions that have a known pH value
and can be dipped into solutions to determine pH value
• what is the theoretical yield.
Answer: maximum amount of product that can be formed in a chemical
reaction. Formed based on the amount of limiting reactant in a chemical
reaction
• what is the molarity of a solution formed from 6.75g NaCL dissolved in
OA FINAL TEST 2026 QUESTIONS WITH
CORRECT ANSWERS GRADED A+
• Miscible.
Answer: Two solvents that mix in any proportion to produce a solution (e.g.,
polar compounds in water).
• PO43-.
Answer: (Phosphate)
• What occurs in a decomposition reaction?.
Answer: one substance splits into two or more simpler substances
• Atomic Number.
Answer: Total number of protons in the nucleus.
• Density of an object? mass of 2.4019 and volume of 1.40mL
2.4019g/1.40mL=.
Answer: density = 1.7156g/mL= 1.72g/ml
• Percent Compostion by mass.
Answer: mass %= mass of element / mass of compound x 100
• what is the percent composition by mass for N in NH6PO4.
Answer: 12.18%
• Tetrahedral.
Answer: 109.5 degrees, 4 bonds
• how many moles of potassium chloride are required to yield 250g of oxygen
in the reaction 2KClO3 -> 2KCl+ 3O2.
Answer: 5.2 mol convert 250.0 grams to moles: moles=mass/ molar mass,
moles = 250.0/32= 7.81 mol molar ratio btwn KClO3 and O2 is 2:3 the 2=x
moles of KClO3 the 3 = 7.81 mol of O2 15.62=3x 15.62/3= x cross
multiplying to get 5.21 moles =# of moles of KClO3 req.
, • Inverse relationship.
Answer: One variable decreases when another variable increases.
• CO32-.
Answer: (Carbonate)
• Solubility Rules.
Answer: Guidelines determining solubility of compounds in water
• Solute.
Answer: Substance present in smaller amount (being dissolved).
• What does the term valence electrons refer to.
Answer: Electrons in the outer most shell.
• what is the correct formula of aluminum iodide.
Answer: Al3++3I− → AlI3
• what is the correct name for a molecule of SO3.
Answer: Sulfur trioxide
• if 14.67g of C2H6 is allowed to react with 39.51g of O2 as shown what
would be the limiting reactant molar mass (g/mole) C2H6= 30.08, O2=
31.998, H2O= 18.015, CO2= 44.08 2C2H6 + 7O2 -> 6H2O + 4CO2.
Answer: O2. in order to consume all the C2H6 we would need 54.62g of O2,
we only have 39.51g
• what role of the electrodes on pH meter.
Answer: they are dipped into the test solution to read the pH. the pH meter
has electrodes that are calibrated with solutions that have a known pH value
and can be dipped into solutions to determine pH value
• what is the theoretical yield.
Answer: maximum amount of product that can be formed in a chemical
reaction. Formed based on the amount of limiting reactant in a chemical
reaction
• what is the molarity of a solution formed from 6.75g NaCL dissolved in
