Solutions Solutions a review A homogeneous mixture They appear as ONE substance Examples tap water vinegar gold jewelry We will learn identify the solute and the solvent in a variety of solutions ID: 504964
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Slide1
Grade 7 Science
SolutionsSlide2
Solutions… a review
A homogeneous mixture
They appear as ONE substance
Examples: tap water, vinegar, gold jewelrySlide3
We will learn:
identify the solute and the solvent in a
variety of solutions
distinguish between soluble and
insoluble substances
describe the concentration and solubility of substances qualitatively and quantitativelySlide4
Solutions have 2 parts:
Solute
The substance that dissolves
(found in less amounts)
SolventThe substance in which the solute dissolves (found in the greatest amounts)Slide5
Solute= Salt in this case
Solvent= WaterSlide6
Page 255: Solute or Solvent?
A. Brass is used to make many objects. Brass is a solution of zinc metal in a copper metal.
B. Hydrogen peroxide is used to disinfect cuts. Hydrogen peroxide is a solution of 3% hydrogen and 97% water.Slide7
Solute or Solvent?
C. Dental amalgam is a metal that is used to fill cavities. It is a solution of mercury in tin.
D. Deicing fluid is a cleaner used to clean car and truck windshields. It is made up of a solution of propylene glycol in water.Slide8
Solutions song!- Journey with Me!
http://www.youtube.com/watch?v=3G472AA3SEsSlide9
Dissolving...
To mix completely (the solute dissolves into the solvent.)
Some substances are able to dissolve better than others.Slide10
For those about to dissolve- we solute you!
http://www.youtube.com/watch?v=VTmfQUNLlMYSlide11
The Particle Theory of Matter states that “
there are attractive forces between the particles”.
How are substances soluble?Slide12
In order to dissolve, the particles must be more strongly attracted to the particles of the solvent than to themselves.
This means that the solute is
soluble
in that solvent.Slide13
If something is ABLE to dissolve then it is soluble.
For example, sugar dissolves in water.Slide14
Particle Theory- Dissolving animationSlide15
If the particles of the solute are more attracted to their own particles than the solvent particles, dissolving does NOT occur. The solute is said to be
insoluble
in that solvent.
(
ie. Mechanical)How are substances insoluble?Slide16
If something is UNABLE to dissolve then it is insoluble.
For example, sand does not dissolve in water.Slide17Slide18
Soluble or Insoluble?
soluble
insolubleSlide19
Solvent or Not?
Some materials are good solvents for some solutes but not others. For example, oil is insoluble in water but soluble in gasoline.Slide20
States of Solutes and Solvents- Put book and workbook away. Hand out exit cards. Below is an example!
Air
Solute: oxygen, carbon dioxide, other gases
Solvent: nitrogen (most of our air is actually Nitrogen!!)
Gas
GasSlide21
Soda:
(a combination of carbon dioxide in water). Identify water or carbon dioxide as the solute/solvent and say which state they are.
Solute: ?
Solvent: ?
State of Solute: ?State of Solvent: ?Slide22
Vinegar:
(a combination of 3% acetic acid and 97% water). Identify water or acetic acid as the solute/solvent and say which state they are.
Solute: ?
Solvent: ?
State of Solute: ?State of Solvent: ?Slide23
Filtered Sea Water:
(salt in water). Identify water or salt as the solute/solvent and say which state they are.
Solute: ?
Solvent: ?
State of Solute: ?State of Solvent: ?Slide24
Brass
(an alloy of a zinc metal in a copper metal) Identify zinc or copper as the solute/solvent and say which state they are.
Solute:?
Solvent: ?
State of Solute: ?State of Solvent: ?Slide25
Grade 7 Science
Concentrations of SolutionsSlide26
Concentration (p 4 of workbook; 264)
The two cups below each had hot water with a tea
bag sitting in them. The time below the cup
indicates how long the tea bag has been in the cup.
10 minutes 2 minutesSlide27
Concentration is…
The quantity of solute that is dissolved in a certain quantity of the solvent.
Can be described
qualitatively
or
quantitatively
.Slide28
Qualitative:
Using words such as like “
dilute
” or
“concentrated”Slide29
Quantitative:
Using numbers. This is especially important when safety is an issue!Slide30
Student Activity…
1. Demo of
qualitative
concentration
2. Demo of
quantitative concentrationSlide31
Student Practice… Quantitative?
#1(a). Food coloring made the water blue.
(b). Adding 3
mL
of food coloring turned 250
mL
of water blue.
Qualitative
QuantitativeSlide32
#2(a). The water became warmer.
(b). The water’s temperature increased by 5 degree Celsius.
Qualitative
QuantitativeSlide33
#3(a). We needed just over a dozen floor tiles for our model room.
(b). We needed 14 floor tiles for our model room.
Qualitative
QuantitativeSlide34
#4(a). The liquid boiled in 5 min.
(b). The liquid took only a few minutes to boil.
Quantitative
QualitativeSlide35
#5(a). The mass of this solid is 5g more than that one.
(b). This solid is heavier than that one.
Quantitative
QualitativeSlide36
#6(a). He drinks eight glasses of water each day.
(b). He drinks 2L of water each day.
Qualitative
QuantitativeSlide37
Dilute vs. Concentrated
Dilute
There is a small mass of dissolved solute for a certain quantity of solvent.
Concentrated
There is a large mass of dissolved solute for a certain quantity of solventSlide38
Dilute vs. Concentrated- Explained Qualitatively Slide39
Dilute vs. Concentrated- Explained Quantitatively Slide40
Saturated vs. Unsaturated
Saturated
Will form when
no
more solute will dissolve at a certain temperature
Unsaturated
More solute is able to dissolve at a certain temperatureSlide41Slide42Slide43
Question to ponder…
Can a solution be considered to be concentrated be unsaturated? ExplainSlide44
Question to ponder…
If there are two glasses on
Kool
Aid on the table, one is unsaturated the other is saturated. How would you be able to tell the difference between the two?Slide45
Question to ponder…
2. It is possible to “
unsaturate
a saturated solution
”. Suggest ways you might be able to do this.
(Hint: How could you make more sugar dissolve in a glass of water?)Slide46
Grade 7 Science
Solutions and SolubilitySlide47
How Does Temperature Affect Solubility?
Complete Core Activity 8-2A page 268-9Slide48
Rate of Dissolving…
Factors that affect the rate of dissolving include:Size of the soluteTemperaturePressureSlide49
Size of Solute
The smaller the solute particles, the quicker they will dissolve
fasterSlide50
Temperature
The higher the temperature, the more solute and the faster the solute will dissolve
fasterSlide51
Pressure
Gases are more soluble in liquids under higher pressure
(see page 267)
Opened bottle decreases pressure and “bubbles” come out of solutionSlide52
Quantitative
Description
Expressed as the amount of solute per unit volume.
Examples: g/L
g/
mL
ppm
(parts per million)
%Slide53
Converting g/
mL to g/L
**Remember there are 1000mL in 1 L.
1g/mL = ? g/L
1 x 1000 = 1000 therefore 1000g/LSlide54
Practice Problems…
0.3g/
mL
= ? g/L
300g/L
8.9g/mL = ? g/L
8900g/L