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Solutions and
Concentration
What is a solution?
Homogeneous mixture of solute and solvent
Solute: substance dissolved
Often a solid
Solvent: substance in which the solute is dissolved
Usually a liquid
Recall Secondary 1-3
Homogeneous mixture
A mixture where you cannot see the difference
between the different substances involved in the
mixture
More definitions
Aqueous solution
Aqua = water
A solution where water is the solvent
I take a spoonful of Nesquik powder and mix it into my
milk to make chocolate milk.
What is the solute?
What is the solvent?
What is the solution?
Example of a solution
Nesquik powder
Milk
Chocolate Milk
What does it mean when something is more concentrated
than something else?
Example
More/less concentrated
What is concentration?
The amount of substance within a given volume
𝐂 =𝑴
𝑽C: concentration
m: mass of solute
V: volume of solution
More/less concentrated?
4L
1L
m=8g
V=4L
m=2g
V=1L
C=𝑚
𝑉
𝐶 =8𝑔
4𝐿C=2g/L
𝐶 =2𝑔
1𝐿C=2g/L
Consider 3 containers of water,
3 L
2 L
1 L
Consider 3 containers of water, each with cubes of sugar
dissolved into them.
Each cube represents an equal amount of sugar dissolved in the
water.
.
.
1 L
3 L
2 L
1 L
3 L
The water from which container would taste the sweetest?
The water from which container would taste the least sweet?
2 L
1 L
2 L
3 L
1 L5
= 5L 2 L
7= 3.5 L 3 L
12= 4 L
Highest
Concentration
of Sugar
Lowest
Concentration
of Sugar
Practice Problem –
Calculating ConcentrationIan is feeling a little under the weather and decides to make himself some tea. To make it a little more appealing he decides to add 15g of sugar to his teapot which contains 1.5L of tea. What is the concentration of his sweetened tea in g/L?
V=1.5L
m=15𝑔 C =𝑚
𝑉
C =15𝑔
1.5𝐿C = 10g/L
Converting Units
kg g mg
x1000 x1000
÷1000 ÷1000
Converting Units
kL L mL
x1000 x1000
÷1000 ÷1000
Practice Problem –
Calculating Concentration2. Jenna made herself 50ml of Kool-Aid by dissolving 2.5g of the
powder into water. What is the concentration of the Kool-Aid in
g/L?V=50ml
V=0.050𝐿
Remember, we need liters!
V=50𝑚𝑙 𝑥1𝐿
1000𝑚𝑙
m=2.5𝑔
C =𝑚
𝑉
C =2.5𝑔
0.050𝐿C = 50g/L
Rearranging the Equations
Example
Emma wants to make 125ml of a 8g/L saline solution. How
much salt will she need to use?
C= 8g/L
m= ?
V = 125ml
= 0.125L
C =𝑚
𝑉8𝑔
1𝐿=
𝑥 𝑔
0.125 𝐿
𝑥 = 1 𝑔
Example
What is the maximum volume that Cory can make of an
80g/L solution of chocolate milk if he only has 23g of Nesquik
powder?
C= 80g/L
m= 23g
V = ? ml
C =𝑚
𝑉80𝑔
1𝐿=23𝑔
𝑥 𝐿
𝑥 = 0.2875𝐿 = 287.5𝑚𝐿
Concentrations in Percent
What is percentage?
“per 100”
Percentage 10
10
What percentage of the squares are grey?
Grey squares
= 20
Total squares
= 100
Percentage
= 20%
We can also measure concentration in % (m/V)
Percent (m/V)
What is the % concentration?
1 ml of water (solvent)
1 g of solute
C=?
m= 2g
V = 25ml
C= 𝑚
𝑉=
2𝑔
25𝑚𝑙
2𝑔
25𝑚𝑙=
𝑥𝑔
100𝑚𝑙
8%
2𝑔
25𝑚𝑙=
8𝑔
100𝑚𝑙
Situation Which drink has the highest
concentration of sugar?
Practice Problem
1. What is the % concentration of sugar in
a 355ml can of Coca-Cola?
C=?
m= 42g
V = 355ml
C= 𝑚
𝑉=
42𝑔
355𝑚𝑙
42𝑔
355𝑚𝑙=
𝑥𝑔
100𝑚𝑙
11.83%
Practice Problem
2. What is the % concentration of sugar in
a 591ml bottle of Gatorade?
C=?
m= 35g
V = 591ml
C= 𝑚
𝑉=
35𝑔
591𝑚𝑙
35𝑔
591𝑚𝑙=
𝑥𝑔
100𝑚𝑙
5.92%
Practice
3. What is the maximum volume that Will can make of an 8%
solution of chocolate milk if he uses 24g of Nesquik powder?
C= 8%
m= 24g
V = ? V=300ml
C= 𝑚
𝑉
8%= 24𝑔
𝑉8𝑔
100𝑚𝑙=
24𝑔
𝑉