HOLD UP
YOUR BOARD!
Chapter 7 Review game
Rules
• Use the same periodic table.
• Use the mass as written on the periodic
table
• Round up your calculations to 2 decimal
points
• Follow significant rule for your final answer
• Do the calculation on the board and circle
your answer
• All your units must be included for full
credit!
• If you get a questions wrong, you are out
until you get the “COME BACK” questions
correct.
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Rules
• Everyone will need to
show their own work on a
separate sheet of paper
for a 1 HW credit.
• The winning team will
receive 5pt extra credit
on the test.
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Question #1
• Find the number of
molecules or ions
2.00 mol Fe 3+
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2.00 mol
6.02 x 1023 ions
1 mol
= 1.20 x 1024 ions
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Question #2
Find the number of
moles.
3.01 x 1023 molecules of
H2 O
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3.01 x 1023 molecules
1 mol
6.02 x 1023 molecules
= 0.500 mol H2O
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Question #3
• Find the number of moles
of sodium ions Na+
Na2CO3
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2 mol of Na+
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Question #4
Find the number of sodium
ions
3.00 mol
Na2CO3
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3.00 mol Na2CO3
2 mol Na+ 6.02 x 1023 ions
1 mol Na2CO3 1 mol Na+
= 3.61 x 1024 atoms
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Question #5
Find the mass in grams
4.30 x 1016 atoms of He
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4.30 x 1018
atoms
1 mol
6.02 x 1023 molecules
4.00 g
1 mol
= 2.86 x 10-7 g He
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COME BACK!!!!!
Find the mass in grams
4.01 x 1023 atoms of Ca
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4.01 x 1023
atoms
1 mol
6.02 x 1023 molecules
40.08 g
1 mol
= 26.7 g Ca
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Question #6
What is the percent
composition of Na in
NaCl?
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NaCl = 22.99 g Na
22.99g Na + 35.45g Cl = 58.44 g NaCl
22.99 g Na
58.44 g NaCl
x 100 %
= 39.34% Na
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Question #7
Determine the empirical
formula of a compound that
is
63.50% Ag,
8.25% N
28.25% O.
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63.50g Ag = 0.59 mol Ag
8.25 g N = 0.59 mol N
28.25 g O = 1.77 mol O
Divide all the mol by 0.59.
AgNO3
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Question #8
Determine the empirical
formula of a compound
that is
56.34% P
And the rest is O.
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56.34g P = 1.82 mol P
43.66 g O = 2.73 mol O
Divide all the mol by 1.82.
PO1.5
Multiply by 2 for whole number ratio
P2O3
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Question #9
A compound has an
empirical formula of CH.
Its molecular mass is 78
g/mol. What is its
molecular formula?
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C = 12.01 g/mol
H = 1.01 g/mol
13.02 g/mol
78 g/mol
13.02 g/mol
6 (CH)
= 5.99
=
=6
C6H6
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Question #10
The empirical formula is
P2O5. Its molar mass is 284
g/mol. Determine the
MOLECULAR formula.
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P x 2 = 30.97 g/mol x 2
O x 5 = 16.00 g/mol x 5
141.94 g/mol
284 g/mol
141.94 g/mol
2 (P2O5)
=2
=
P4O10
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