Chem 133 Exam 2 | Questions with 100% Verified Answers |
Latest Update 2026/2027
Question: What is the mass in grams of 9.76 × 10^12 atoms of naturally
occurring sodium?
Answer: First we get the moles : 9.76 x 10^.02 x 10^23 =1.62 x 10^-11
second we multiply by the atomic mass :
1.62 x 10^-11 mol x 22.9898 g/mol=3.73 x 10^-10 g
Question: How many oxygen atoms are contained in 2.74 g of
Al2(SO4)3?
Answer: 2.74 grams Al2(SO4)3 x 1 mol Al2(SO4).17 grams Al2(SO4)3 x
12 mol O / 1 mol Al2(SO4)3 x 6.022x10^23 Oxygen atoms / 1mole O
= 5.79 x 10^22 Oxygen atoms
Question: Which one of the following is a diprotic acid?
Answer: Diprotic' is a fancy term that means 'two protons.' If you're looking for a diprotic acid,
you're looking for one that can give off two protons when it dissociates. Another way to
say 'proton,' is 'hydrogen ion,' so you're looking for the acid that has two hydrogens in
front of it. That's your diprotic acid.
Question: The balanced net ionic equation for precipitation of CaCO3
when aqueous solutions of Na2CO3 and CaCl2 are mixed is
________.
Answer: Ca2+(aq) + CO3 2- (aq) → CaCO3 (s)
Question: The net ionic equation for the reaction between aqueous
sulfuric acid and aqueous sodium hydroxide is ________.
Answer: e ionic equation for any acid reacting with any base is: H+(aq) + OH-(aq) --> H2O(l)
The H2SO4 provides the H+ ions. The OH- ions come from the sodium hydroxide. The
sodium ions and the sulphate ions remain unchanged in solution so they are called
spectator ions and are not used in the ionic equation
Question: What is the mass % of aluminum in aluminum sulfate
(Al2(SO4)3) rounded to three significant figures?
Answer: To find the percent composition of Al₂(SO₄)₃, you divide the total mass of each atom
by
the molecular mass and multiply by 100 %.
Question:
Answer: Explanation:
% by mass =
mass of component/
total mass
× 100 %
, Question:
Answer: Mass of 2 Al atoms = 2 Al atoms ×
26.98
/
1
Al atom
= 53.96 u.
Question:
Answer: Mass of 3 S atoms = 3 S atoms ×
32.06
/
1
S atom
Question:
Answer: = 96.18 u
Mass of 12 O atoms = 12 O atoms ×
16.00
/
1
O atom
= 192.0 u
Question:
Answer: Mass of 1 Al₂(SO₄)₂ formula unit = (53.96 + 96.18 + 192.0) u = 342.1 u
Question:
Answer: % of Al =
mass of Al
total mass
× 100 % =
53.96
/
342.1
u
× 100 % =15.77 %
Question: The correct name for HBrO4 is ________.
Answer: perbromic acid
Question: An aqueous ethanol solution (400 mL) was diluted to 4.00 L,
giving a concentration of 0.0400 M. The concentration of the
original solution was ________ M.
Answer: Molarity = moles / L
moles = Molarity x L = 0.0400 x 4.00 = 0.16
Molarity of the original solution was 0..400 = 0.400 M
Latest Update 2026/2027
Question: What is the mass in grams of 9.76 × 10^12 atoms of naturally
occurring sodium?
Answer: First we get the moles : 9.76 x 10^.02 x 10^23 =1.62 x 10^-11
second we multiply by the atomic mass :
1.62 x 10^-11 mol x 22.9898 g/mol=3.73 x 10^-10 g
Question: How many oxygen atoms are contained in 2.74 g of
Al2(SO4)3?
Answer: 2.74 grams Al2(SO4)3 x 1 mol Al2(SO4).17 grams Al2(SO4)3 x
12 mol O / 1 mol Al2(SO4)3 x 6.022x10^23 Oxygen atoms / 1mole O
= 5.79 x 10^22 Oxygen atoms
Question: Which one of the following is a diprotic acid?
Answer: Diprotic' is a fancy term that means 'two protons.' If you're looking for a diprotic acid,
you're looking for one that can give off two protons when it dissociates. Another way to
say 'proton,' is 'hydrogen ion,' so you're looking for the acid that has two hydrogens in
front of it. That's your diprotic acid.
Question: The balanced net ionic equation for precipitation of CaCO3
when aqueous solutions of Na2CO3 and CaCl2 are mixed is
________.
Answer: Ca2+(aq) + CO3 2- (aq) → CaCO3 (s)
Question: The net ionic equation for the reaction between aqueous
sulfuric acid and aqueous sodium hydroxide is ________.
Answer: e ionic equation for any acid reacting with any base is: H+(aq) + OH-(aq) --> H2O(l)
The H2SO4 provides the H+ ions. The OH- ions come from the sodium hydroxide. The
sodium ions and the sulphate ions remain unchanged in solution so they are called
spectator ions and are not used in the ionic equation
Question: What is the mass % of aluminum in aluminum sulfate
(Al2(SO4)3) rounded to three significant figures?
Answer: To find the percent composition of Al₂(SO₄)₃, you divide the total mass of each atom
by
the molecular mass and multiply by 100 %.
Question:
Answer: Explanation:
% by mass =
mass of component/
total mass
× 100 %
, Question:
Answer: Mass of 2 Al atoms = 2 Al atoms ×
26.98
/
1
Al atom
= 53.96 u.
Question:
Answer: Mass of 3 S atoms = 3 S atoms ×
32.06
/
1
S atom
Question:
Answer: = 96.18 u
Mass of 12 O atoms = 12 O atoms ×
16.00
/
1
O atom
= 192.0 u
Question:
Answer: Mass of 1 Al₂(SO₄)₂ formula unit = (53.96 + 96.18 + 192.0) u = 342.1 u
Question:
Answer: % of Al =
mass of Al
total mass
× 100 % =
53.96
/
342.1
u
× 100 % =15.77 %
Question: The correct name for HBrO4 is ________.
Answer: perbromic acid
Question: An aqueous ethanol solution (400 mL) was diluted to 4.00 L,
giving a concentration of 0.0400 M. The concentration of the
original solution was ________ M.
Answer: Molarity = moles / L
moles = Molarity x L = 0.0400 x 4.00 = 0.16
Molarity of the original solution was 0..400 = 0.400 M
