Transcript Slide 1

#47 Give three common ways that matter
is measured. Give examples of each
Counting: Example, counting sheep
Volume: Example: estimating the #
of jelly beans in a large jar.
Mass: Example: Weighing out some
NaCl.
#48 Name the representative particle
of each substance:
a. oxygen gas O2 (a molecule)
b. sodium sulfide Na2S (a formula unit)
c. sulfur dioxide SO2 (a molecule)
d. potassium
K (an atom)
#49 How many hydrogen atoms are
in a representative particle of each
substance?
a. Al(OH)3
3
b. H2C2O4
2
c. (NH4)2HPO4 9
d. C4H10O
10
#50 Which contains more molecules:
1.00 mole H2O2 , 1.00 mole of C2H6,
or 1.00 mole CO?
They all contain exactly the same:
6.02 x 1023 molecules
#51 Which contains more atoms:
1.00 mole of H2O2 ,
1.00 mole of C2H6,
or 1.00 mole of CO?
Since H2O2 contains 4 atoms per
molecule, C2H6 contains 8 atoms
per molecule, and CO only 2 atoms
per molecule;
1 mole of C2H6 contains the
most atoms (6.02 x 1023 times 8)
#52 Find the number of representative particles in each substance:
a. 3.00 moles Sn = (6.02 x 1023 times 3)
b. 0.400 moles KCl = (6.02 x 1023 times .4)
c. 7.50 moles SO2 = (6.02 x 1023 times 7.5)
d. 4.80 x 10-3 moles NaI =
(6.02 x 1023 times .0048)
#53 Calculate the molar mass
of each substance:
a. H3PO4 = 98.0 g/mole
b. N2O3 = 76.0 g/mole
c. CaCO3 = 100.1 g/mole
d. (NH4)2SO4 = 132.1 g/mole
e. C4H9O2 =
89.0 g/mole
f. Br2 =
159.8 g/mole
#54 Calculate the mass of 1.00 mole
of each of these substances
the mass on one mole of something
is just its molar mass…
a. SiO2 = 60.1 g/mole
b. N2
= 28.0 g/mole
c. Fe(OH)3 = 106.8 g/mole
d. Cu
= 63.5 g/mole
#58 How many moles is each of the
following:
In each of these you simply divide by the
molar mass of each compound
a. 15.5 g SiO2
15.5 g x 1 mole
(28.1 + 32)
= .258 moles
b. .0688 g AgCl
4.80x10-4 moles
c. 79.3 g Cl2
1.12 mole
d. 5.96 g KOH
.106 mole
e. 937 g Ca(C2H3O2)
f. .800 g Ca
5.93 mole
.020 mole
#59 Find the mass of each substance.
In each of these you multiply by the
molar mass
a. 1.50 mole C5H12 = 108 grams
b. 14.40 mole F2 = 547 grams
c. .780 mole Ca(CN)2 = 71.8 grams
d. 7.00 mole H2O2 = 238 grams
e. 5.6 mole NaOH = 224 grams
f. 3.21 x 10-2 mole Ni = 1.88 grams
#60 Calculate the volume of each of the
following gases at STP.
The volume of any gas at STP is
22.4 liters per mole
a. 7.6 moles Ar
x 22.4 liters = 1.7 x 102 liter
1 mole
b. .44 moles C2H6
x 22.4 liters = 9.9
1 mole
liter
#61 What is the density of each of the
following gases at STP.
(density is in units of grams/liter)
a. C3H8
The molar mass is: (12x3 +8) = 44
44 g
x 1 mole =
1 mole 22.4 liters
b. Ne
1.96 g
liter
The molar mass is: 20.2
20.2 g x 1 mole =
1 mole
22.4 liters
.902 g
liter
#61 What is the density of each of the
following gases at STP.
(density is in units of grams/liter)
c. NO2
The molar mass is: (14+32) = 46
46 g
x 1 mole =
1 mole 22.4 liters
2.05 g
liter
#62 Find each of the following
quantities:
a. the volume, in liters, of 835 g SO3
835 g x 1 mole x 22.4 liters =
1 mole
1
80.1
234 Liters SO3
#62 Find each of the following
quantities:
b. the mass in grams, of a molecule
of aspirin (C9H8O4)
22.4 liters =
1 mole
1 molecule x
1 mole
x
1
6.02 x 1023 molecules
180 g =
1 mole
2.99 x 10-22 grams
#62 Find each of the following
quantities:
c. The number of atoms in 5.78 moles
NH4NO3
5.78 moles x
1
6.02 x1023 molecules
1 mole
9 atoms
= 3.13 x 1025 atoms
1 molecule NH4NO3
#63 Calculate the percent composition
of each compound.
a. H2S
The total is: (1.0 x 2) + 32.1= 34.1
% comp. H is: 2.0 x 100 = 5.9%
34.1
% comp. S is: 32.1
34.1
x 100 = 94.1%
#63 Calculate the percent composition
of each compound. The total is:
b. (NH4)2C2O4
(18.0 x 2) +24.0 + 64.0
= 124.0
% comp. N is: 28.0
124.0
% comp. H is:
x 100 = 22.6%
8.0 x 100 = 6.5%
124.0
% comp. C is: 24.0 x 100 = 19.4%
124.0
% comp. O is: 64.0 x 100 = 51.6%
124.0
#63 Calculate the percent composition
of each compound. The total is:
c. Mg(OH)2
24.3 +(17.0 x 2)
= 82.6
% comp. Mg is: 24.3
82.6
x 100 = 41.7%
% comp. O is:
32.0 x 100 = 54.9%
82.6
% comp. H is:
2.0 x 100 = 3.4%
82.6
#63 Calculate the percent composition
of each compound. The total is:
d. Na3PO4
(23.0 x 3) + 31.0 + 64.0
= 164.0
% comp. Na is: 69.0 x 100 = 42.1%
164.0
% comp. P is:
31.0 x 100 = 18.9%
164.0
% comp. O is:
64.0 x 100 = 39.0%
164.0