BIO-CHEMISTRY FINAL EXAM QUESTIONS AND 100%
CORRECT DETAILED ANSWERS LATEST UPDATE 2025
GRADED A+
Between which two atoms are ionic bonds most likely to form? (Draw electron-dot structures to help you
decide.)
A) K and F
B) O and O
C) C and H
D) N and O -ANSWER: A) K and F
ionic bonds are between a nonmetal and a metal
Which of the following correctly illustrates the Lewis structure for a covalent compound? -
ANSWER: H
D) H-C- H
H
covalent= two nonmetals
Lewis structures use dots to depict valence electrons. For the following elements, what pattern in the
corresponding Lewis dot structures can you identify?
lead (Pb) antimony (Sb) sulfur (S) chlorine (Cl)
A. The dot structure for each contains the same number of outer electrons.
B. The number of outer electrons increases by 2 for each element.
C. The number of outer electrons increases by 1 for each element.
D. The number of outer electrons corresponds to the total number of electrons in each element -
ANSWER: C. The number of outer electrons increases by 1 for each element.
,The Lewis structure of HCN contains
A. one double bond and one single bond.
B. one triple bond and one single bond
C. two single bonds.
D. two double bonds -ANSWER: B. one triple bond and one single bond
Which of the following molecules contains a double bond?
A. COCl2
B. C2H6
C. CF4
D. SF -ANSWER: A. COCl2
Which of the following represents the correct Lewis dot structure for sodium chloride? -ANSWER:
C. Na+ +[:..Cl..:]-
The first step in constructing a Lewis dot structure for a molecule is to determine how many valence
electrons are in all of the atoms contained in the molecule. How many total valence electrons are
contained in the atoms of a molecule of butane, C4H10? -ANSWER: 26 e-
According to the law of conservation of mass, the total mass of the reacting substances is
A. always more than the total mass of the products.
B. always less than the total mass of the products.
C. sometimes more and sometimes less than the total mass of the products.
D. always equal to the total mass of the products -ANSWER: D. always equal to the total mass of the
products
To balance a chemical equation, you may adjust the
, A. coefficients.
B. subscripts.
C. formulas of the products.
D. either the coefficients or the subscripts. -ANSWER: A. coefficients
Which is the balanced chemical equation for the following formula equation: (NH4)2S = NH3 + H2S -
ANSWER: C. (NH4)2S = 2NH3 + H2S
Determine the missing reactant for the following combustion reaction: 2 ______ +
15O2→14CO2+6H2O.
A. C14H12
B. C14H12O4
C. C7H6
D. C7H6O2 -ANSWER: D. C7H6O2
Which of the following statements is true about the reaction 2F2 + 2H2O → 4HF + O2?
A. Two grams of O2 are produced when 2 g of F2react with 2 g of H2O.
B. Two moles of HF are produced when 1 mol of F2reacts with 1 mol of H2O.
C. For every 2 mol O2 produced, 6 mol HF are produced.
D. For every 1 mol H2O that reacts, 2 mol O2 are produced. -ANSWER: B. Two moles of HF are
produced when 1 mol of F2reacts with 1 mol of H2O.
CORRECT DETAILED ANSWERS LATEST UPDATE 2025
GRADED A+
Between which two atoms are ionic bonds most likely to form? (Draw electron-dot structures to help you
decide.)
A) K and F
B) O and O
C) C and H
D) N and O -ANSWER: A) K and F
ionic bonds are between a nonmetal and a metal
Which of the following correctly illustrates the Lewis structure for a covalent compound? -
ANSWER: H
D) H-C- H
H
covalent= two nonmetals
Lewis structures use dots to depict valence electrons. For the following elements, what pattern in the
corresponding Lewis dot structures can you identify?
lead (Pb) antimony (Sb) sulfur (S) chlorine (Cl)
A. The dot structure for each contains the same number of outer electrons.
B. The number of outer electrons increases by 2 for each element.
C. The number of outer electrons increases by 1 for each element.
D. The number of outer electrons corresponds to the total number of electrons in each element -
ANSWER: C. The number of outer electrons increases by 1 for each element.
,The Lewis structure of HCN contains
A. one double bond and one single bond.
B. one triple bond and one single bond
C. two single bonds.
D. two double bonds -ANSWER: B. one triple bond and one single bond
Which of the following molecules contains a double bond?
A. COCl2
B. C2H6
C. CF4
D. SF -ANSWER: A. COCl2
Which of the following represents the correct Lewis dot structure for sodium chloride? -ANSWER:
C. Na+ +[:..Cl..:]-
The first step in constructing a Lewis dot structure for a molecule is to determine how many valence
electrons are in all of the atoms contained in the molecule. How many total valence electrons are
contained in the atoms of a molecule of butane, C4H10? -ANSWER: 26 e-
According to the law of conservation of mass, the total mass of the reacting substances is
A. always more than the total mass of the products.
B. always less than the total mass of the products.
C. sometimes more and sometimes less than the total mass of the products.
D. always equal to the total mass of the products -ANSWER: D. always equal to the total mass of the
products
To balance a chemical equation, you may adjust the
, A. coefficients.
B. subscripts.
C. formulas of the products.
D. either the coefficients or the subscripts. -ANSWER: A. coefficients
Which is the balanced chemical equation for the following formula equation: (NH4)2S = NH3 + H2S -
ANSWER: C. (NH4)2S = 2NH3 + H2S
Determine the missing reactant for the following combustion reaction: 2 ______ +
15O2→14CO2+6H2O.
A. C14H12
B. C14H12O4
C. C7H6
D. C7H6O2 -ANSWER: D. C7H6O2
Which of the following statements is true about the reaction 2F2 + 2H2O → 4HF + O2?
A. Two grams of O2 are produced when 2 g of F2react with 2 g of H2O.
B. Two moles of HF are produced when 1 mol of F2reacts with 1 mol of H2O.
C. For every 2 mol O2 produced, 6 mol HF are produced.
D. For every 1 mol H2O that reacts, 2 mol O2 are produced. -ANSWER: B. Two moles of HF are
produced when 1 mol of F2reacts with 1 mol of H2O.
