Transcript Slide 1

#1) If 0.20 bushel is 1 dozen apples and a dozen
apples has a mass of 2.0 kg, what is the mass
of 0.50 bushel of apples?
.20 bushel
1 dozen apples
0.5 bushel
l
____2.0 Kg___
1 dozen apples
2.0 Kg
1 dozen apples
X
X 1 dozen apples
.2 bushel
= 5.0 Kg
#2 Assume 2.0 kg of apples is 1 dozen and
that each apple has 8 seeds. How many
apple seeds are in 14 kg of apples?
8 seeds
1 apple
1 dozen apples
2.0 kg
14 kg apple X 1 dozen X 12 apples
2.0 kg 1 dozen
1
8
seeds
X
1 apple
=
672 seeds
3) How many moles is 2.80 x 1023 atoms
of silicon?
2.80 x 1023atoms X 1 mole
23atoms
6.02
x
10
1
4.65 mol Si
4) How many moles is 2.17 x 1023
representative particles of bromine?
the representative particle for bromine is
Br2
2.17 x 1023 part. X 1 mole
24 part.
6.02
x
10
1
.360 mol Br2
5) How many atoms are in 1.14 mol
SO3
4 atoms
X 1.14 mole X 6.02 molecules
1 molecule
1
1 mole
2.75 x 1024 atoms
6) How many moles are in 4.65 x 1024
molecules of NO2
SO3
4.65 x 1024 molecules of NO2 X 1 mole
24 molecules
6.02
x
10
1
7.72 moles
#7 Find the molar mass of PCl3
To find the molar mass simply add
up the atomic masses of the atoms
in the molecule (4 atoms total here)
P =30.97amu
Cl=35.4amu
30.97 + 35.4 + 35.4 + 35.4 = 106.5 g
#8 What is the mass of 1.00 mol of
sodium hydrogen carbonate?
NaHCO3 consists of 6 atoms total in
one formula unit. Adding them up you
get:
Na = 23.0g/mol
C = 12.0g/mol
H = 1g/mol
O= 16g/mol
23.0 + 1 + 12.0 + 16 + 16 + 16 = 84.0
g
#9 What are three ways to measure the
amount of something?
simple counting
volume
weight
#10 Describe the relationship between
Avogadro’s number and one mole of any
substance.
Avogadro’s number is the number of
representative particles you have in one
mole which is 6.02 x 1023
#11 How is the atomic mass of an element
related to the molar mass of the element?
The atomic mass is the number of grams
of an element that you need to have exactly
one mole of that substance ie. 6.02 x 1023
particles.
#12 How can you calculate the mass of a
mole of a compound?
You add up the individual atomic masses
of each atom within the formula of
the compound.
example: H2O is
1g+1g+16g = 18 grams
1 mole
#13 How many moles is 1.50 X 1023
molecules NH3?
1.50 X 1023 molecules NH3
1
1 mole NH3
X 6.02 x 1023 molecules
2.49 x 10-1 mole NH3
#14 How many atoms are in 1.75 moles
of CHCl3?
23 atoms
6.02
x
10
1.75 moles of CHCl3 X
1 mole
1
5.27 x 1024 atoms
#15 What is the molar mass of CaSO4?
Ca =40.08
S = 32.0
O = 16
40.08 + 32.0 + 16 + 16 + 16 = 136.2 g/mol