WGU D425 INTRODUCTION TO CHEMISTRY
OA CERTIFICATION SCRIPT 2026
QUESTIONS WITH SOLUTIONS GRADED A+
• Noble Gases (Group 8/18).
Answer: Atoms with completely filled energy levels (eight electrons in their
outermost shell) - non-reactive and generally do NOT form compounds.
• Kilo (k).
Answer: 10^3 (1000)
• Neutrons (n0).
Answer: Neutral charge, located in the nucleus.
• C2H3O2-.
Answer: (Acetate)
• according to the Arrhenius concept, what does an acid do?.
Answer: it increases the concentration of H+ in an aqueous solution ( when
dissolved in water)
• Micro (m).
Answer: 10^-6 (0.000001)
• naturally occurring boron (B) is composed of 19.9% of B-10(10.013amu)
and 80.1% of B-11 (11.009amu) what is the average atomic mass of boron?.
Answer: 10.81 amu
• Example of Molarity.
Answer: 6.75g NaCl in 452mL H2O -> 0.256M.
• term (aq) stands for aqueous. what is the name of the following acid:
HF(aq).
Answer: Hydrofluoric acid. prefix hydro is placed in front of the nonmetal
with a name that ends in -ic. if HF were in a gaseous state, the name of the
acid would be hydrogen fluoride. the element name is used to name the
, cation, and the name of the anion ends with -ide
• Empirical Formula.
Answer: Simplest whole number ratio of atoms.
• Double Replacement.
Answer: Two elements in different compounds trade places (AB + CD ->
AD + CB). Often form a solid (precipitation reaction).
• Synthesis reaction.
Answer: a reaction in which two or more substances combine to form a new
compound
• Solvent.
Answer: Substance present in larger amount (doing the dissolving).
• Double Replacement.
Answer: AB + CD --> AD + CB a chemical reaction where two elements in
different compounds trade places
• What characterizes a noble gas.
Answer: elements in group 8a with completely filled energy levels.
• Density converted between mass and volume of a substance 30.2ml sample
of ethyl alcohol with a mass of 23.71002g.
Answer: p=0.785g/ml
• Common metal ions.
Answer: Familiarity with charges of group 1, group 2, Al, silver, zinc,
cadmium
• OH-.
Answer: (Hydroxide)
• Potential Energy.
Answer: Stored energy.
• 45.599g of phosphorous (P4) were allowed to react w/ 67.900g of oxygen
(O2). If 95.201g of P4O10 were actually produced in the lab what is the
OA CERTIFICATION SCRIPT 2026
QUESTIONS WITH SOLUTIONS GRADED A+
• Noble Gases (Group 8/18).
Answer: Atoms with completely filled energy levels (eight electrons in their
outermost shell) - non-reactive and generally do NOT form compounds.
• Kilo (k).
Answer: 10^3 (1000)
• Neutrons (n0).
Answer: Neutral charge, located in the nucleus.
• C2H3O2-.
Answer: (Acetate)
• according to the Arrhenius concept, what does an acid do?.
Answer: it increases the concentration of H+ in an aqueous solution ( when
dissolved in water)
• Micro (m).
Answer: 10^-6 (0.000001)
• naturally occurring boron (B) is composed of 19.9% of B-10(10.013amu)
and 80.1% of B-11 (11.009amu) what is the average atomic mass of boron?.
Answer: 10.81 amu
• Example of Molarity.
Answer: 6.75g NaCl in 452mL H2O -> 0.256M.
• term (aq) stands for aqueous. what is the name of the following acid:
HF(aq).
Answer: Hydrofluoric acid. prefix hydro is placed in front of the nonmetal
with a name that ends in -ic. if HF were in a gaseous state, the name of the
acid would be hydrogen fluoride. the element name is used to name the
, cation, and the name of the anion ends with -ide
• Empirical Formula.
Answer: Simplest whole number ratio of atoms.
• Double Replacement.
Answer: Two elements in different compounds trade places (AB + CD ->
AD + CB). Often form a solid (precipitation reaction).
• Synthesis reaction.
Answer: a reaction in which two or more substances combine to form a new
compound
• Solvent.
Answer: Substance present in larger amount (doing the dissolving).
• Double Replacement.
Answer: AB + CD --> AD + CB a chemical reaction where two elements in
different compounds trade places
• What characterizes a noble gas.
Answer: elements in group 8a with completely filled energy levels.
• Density converted between mass and volume of a substance 30.2ml sample
of ethyl alcohol with a mass of 23.71002g.
Answer: p=0.785g/ml
• Common metal ions.
Answer: Familiarity with charges of group 1, group 2, Al, silver, zinc,
cadmium
• OH-.
Answer: (Hydroxide)
• Potential Energy.
Answer: Stored energy.
• 45.599g of phosphorous (P4) were allowed to react w/ 67.900g of oxygen
(O2). If 95.201g of P4O10 were actually produced in the lab what is the
