1. Science 8 Unit A
Mix & Flow of Matter

2. Goals of this Unit: Identify WHMIS and HHPS symbols
Describe safety precautions for using substances
Identify examples of fluids in products and devices
Describe examples of fluids used to transport, process, or use materials
Identify important properties of fluids
Distinguish between pure substances and mixtures

3. Goals (Continued) Define concentration and solubility
Identify factors that affect solubility and rate of dissolving
Describe the particle model of matter
Relate the behaviour of mixtures to the particle model of matter
Define viscosity and describe how temperature affects it
Calculate and compare densities
Relate density to the particle model of matter

4. Goals (Continued) Describe methods for altering the density of fluids
Explain buoyancy
Describe pressure and examples of its use
Compare the compressibility of liquids and gases
Describe examples of technologies based on solubility

5. Goals (Continued)
Describe examples of technologies based on the flow rates of moving liquids
Explain how to design and construct a working model of a fluid-using device

6. 1.1 – WHMIS Symbols and Safety Procedures
Take a look at Figure 1.1 on page 9
What are some unsafe lab practices that are taking place?

7. WHMIS
WHMIS is an acronym that represents: W H M I S

8. WHMIS Symbols

9. HHPS WHMIS is used in workplaces
However, you may have noticed that many products that you have at home have a different set of symbols
These symbols are known as HHPS H P S

10. HHPS Symbols
Level of Hazard

11. Safety in the Lab
Safety is always our first concern when we carry out any activity
Before starting any activity, be prepared to:
Follow safety procedures outlined by the teacher and the text
Keep your eyes open for possible hazards, and report them immediately
Show respect and concern for your own safety and the safety of your clasmates and teacher

12. 1.2 – The Many Uses of Fluids
Some examples of fluids are:

13. Uses of Fluids Slurries: Manufacturing Solids:
Holding Other Substances:

14. Useful Properties of Fluids
Fluids have a number of important properties
These properties are:
Viscosity
Density
Buoyancy
Compressibility

15. 2.1 – Pure Substances and Mixtures
All matter can be classified as either pure substances or mixtures
Pure Substance:
Mixture:

16. Mechanical Mixtures and Solutions
Mixtures can be classified as either mechanical mixtures or solutions
Mechanical Mixtures
Solutions

17. Suspensions and Colloids
Cloudy mixtures can be classified as suspensions or colloids
Suspensions
Colloids

18. Matter Classification Chart

19. Classifying Substances
Fluid
Pure Substance
Solution
Soda Pop
Hot Chocolate
Distilled Water
Apple Juice
Windshield Washer Fluid

20. More Classifying of Substances
Type of Matter
Baking Soda
Muddy Water
Chocolate Chip Cookie Dough
Gold (14 K)
Gold (24 K)
Whipped Cream

21. Paper Chromatography
Paper chromatography can be used to test whether or not a fluid is a pure substance or a solution
In this technique, a piece of filter paper is placed in a container with the fluid

22. If the fluid is a pure substance, the solvent will carry that substance to a single level
However, if the fluid is a solution, the substances will separate and move at different rates

23. For instance, this black ink is a solution of three different inks

24. How Does it Work?
The substances in the solution are attracted with different strengths to the paper
The substances that are most strongly attracted to the paper do not move very far, but those that have the weakest attraction move the farthest

25. Applications of Chromatography
Chromatography, in many different forms, can be used in a number of different fields, such as:
Forensics
Analytical chemistry
Food analysis
Environmental sciences
Biological research
Medical research

26. 2.2 – Concentration and Solubility
Solutions consist of two parts: a solute and a solvent
Solute
Solvent

27. Measuring Concentration
The concentration of a solution describes the amount of solute in a given amount of solvent
Concentrations can be described in a number of ways:
grams / 100 mL
percent (by volume or weight)
parts per million (ppm) or parts per billion (ppb)
moles per litre (used in chemistry)

28. Comparing Concentrations
A student dissolves 10 g of salt in 50 mL of water. Another student dissolves 25 g of salt in 100 mL of water. Which is more concentrated? How can you tell?

29. Saturated and Unsaturated Solutions
All solutions have a given solubility at a certain temperature
Solubility
The solubility of a substance at a certain temperature defines its saturation point

30. Therefore, solutions can be defined as saturated or unsaturated

31. The Solubility of Common Substances
Solubility in g / 100 mL of Water at 0oC
Compound
Solubility
Salt
35.7
Baking soda
6.9
Carbon dioxide
0.35
Sugar
180
Hydrogen
Oxygen
0.007
Ammonia 92

32. 2.3 – Factors Affecting Solubility
Solubility depends on at least three factors:
Type of solute
Type of solvent
Temperature

33. Type of Solute and Solvent
Solutes and solvents are often classified as polar or non-polar based on their chemical structure
Similar molecules (for example, a polar solute and solvent) will have high solubility
This explains why some paints and dyes can be removed with water while others require a different solvent

34. Temperature
For most common solid or liquid substances, solubility increases as temperature increases
However, for gases, the reverse is true – the higher the temperature, the lower the solubility

35. Thermal Pollution
This means that thermal pollution (warm waste water) from power plants and industries that enters lakes and streams reduces the amount of oxygen that can remain dissolved in the water
As a result, many organisms can die or be forced to migrate to other areas if the water becomes too warm

36. 2.4 – The Particle Model of Matter and the Behaviour of Mixtures
The particle model of matter helps to explain a number of properties of various substances
This model consists of four main points:

37. 1 – All Matter is Made up of Tiny Particles

38. 2 – The Tiny Particles of Matter are Always Moving

39. 3 – The Particles in Matter may be Attracted or Bonded to Each Other

40. 4 – The Particles Have Spaces Between Them

41. The Particle Model and Mixing of Substances
When two substances are mixed, the particles of the solute fill in the spaces between the particles of the solvent
This sometimes means that the total volume after mixing two substances is less than the sum volume of the substances before they are mixed

42. The particle model also explains why substances dissolve
The particles in the solute are attracted to the solvent particles
Therefore, the solvent “pulls apart” the solute, causing it to dissolve

43. Factors Affecting Rate of Dissolving
Temperature
Size of Pieces
Stirring

44. 3.1 – Viscosity and the Effects of Temperature
All fluids flow, but some flow more quickly than others
This is due to a fluid’s viscosity
Viscosity

45. What Determines Viscosity?
Viscosity is due to the internal friction between the molecules in a fluid
Therefore, high viscosity fluids have a large amount of internal friction

46. Temperature and Viscosity
As the temperature of a fluid increases, its viscosity decreases
The particle model of matter can explain this:

47. Measuring Viscosity
The ramp method involves pouring a fluid down a ramp and timing how long it takes for the fluid to reach the bottom
The slower the time, the greater the viscosity of the fluid
This can also be used to confirm the effect that temperature has on viscosity

48. 3.2 – Density of Fluids Density
Not all substances have the same density
This is because they are made of different types of matter
What happens when people misunderstand density…

49. Calculating Density Density is calculated using the following formula:
Density = mass ÷ volume
The most common units for density are g/mL and kg/L for fluids and g/cm3 for solids

50. Example
Joe uses a beaker that has a mass of 75.0 g in a density experiment. He puts 120 mL (or 120 cm3) of sand into the beaker. The mass of the sand and beaker is 270 g. What is the density of the sand?

51. Comparing Density on Graphs
On the graph, which substance
Has the greatest denisty
Has the least density
Has a density of about 1.0 g/mL

52. 3.3 – Density, Temperature, and Buoyancy
Density can change with temperature
This can be explained using the particle model of matter
Solid
Liquid
Gas

53. But What About Water? Water becomes less dense as it becomes a solid
This is because the water molecules arrange themselves in a specific shape that has large amounts of empty space
As a result, water expands and becomes less dense when it freezes

54. Changing Density by Changing Concentration
If we add a solute to a solvent, the density of the solution will change
This is because there are more particles in a given volume, which means the solution is more dense
Distilled Water (1 g/mL)
Salt Water (1.02 g/mL)

55. Buoyancy
Buoyancy
Buoyancy depends on two forces:

56. Positive, Negative and Neutral Buoyancy
Positive Buoyancy
Negative Buoyancy
Neutral Buoyancy

57. Applications of Buoyancy
Several transportation technologies rely on buoyancy
Cargo ships have markings known as a Plimsoll Line painted on their hulls
This line shows how heavily the ship can be loaded for various weather conditions

58. Balloons and Blimps
Both balloons and blimps rely on buoyancy to stay in the air
Hot air balloons heat air and trap it, creating a low-density pocket of air that floats in the cooler air around it
Blimps use a number of gases that are less dense than air (mostly helium) to float
The Hindenburg Disaster (1937)

59. 3.4 – Compression of Fluids
Compressibility
However there are differences in the compressibility of different fluids

60. Comparing Compressibility of Liquids and Gases
Gases are much easier to compress than liquids
This can be explained through the particle model of matter
Liquid
Gas

61. 3.5 – Pressure in Fluids – Pascal’s Law
Pressure is measured in pascals (Pa), or occasionally in N/cm2
Ex: A force of 350 N is exerted over an area of 2.0 m. What is the pressure produced?

62. Blaise Pascal
Blaise Pascal was a French mathematician who studied how pressure affects a fluid
He investigated both the relationship between pressure and depth, and the affect of applying force to a fluid in a closed container

63. Pressure and Depth
Pascal determined that as the depth of a fluid increased, the pressure also increased
Reason:

64. Pascal’s Law
Pascal studied how forces affect fluids in a closed system
He developed Pascal’s Law:

65. Applying Pascal’s Law – Hydraulic Systems
A hydraulic system is a fluid placed in an enclosed system that is made up of two pistons and a connecting tube
When force is placed on one piston, it transmits the force through the fluid (in all directions) and forces the other piston to move

66. Advantages of Hydraulic Systems
Hydraulic systems allow us to increase the force that is exerted on an object
Therefore, we can use a small force to move or lift a very large object

67. Pneumatic Systems
Pneumatic systems are similar to hydraulic system, but they use compressed air or gases instead of a liquid
The compressed air moves parts within the system, which causes the device to operate

68. Maintaining Pressure
Pneumatic and hydraulic systems must operate under pressure
If a leak develops in the system, the entire system would fail

69. 4.1 – Technologies Based on Solubility
A number of technologies rely on solubility
Most cleaners use the principle of solubility to operate
Detergents have surfactants which attach themselves to oil and dirt particles and pull them off of fabrics and other materials
These surfactants make the dirt and oil soluble in water

70. How do Surfactants Work?
Surfactants have one end that attaches to water molecules and another end that attaches to oils
This allows the normally insoluble oils to be dissolved in water

71. Diving and Decompression
At high water pressures, more nitrogen gas dissolves in our blood than normal
When a diver returns to the surface, this nitrogen gas leaves the blood
However, if a diver returns too quickly, nitrogen bubbles suddenly form in the blood (similar to the bubbles that form when you open a bottle or can of pop)

72. The Bends
When these bubbles form, they collect in the joints, causing severe pain
As well, if bubbles occur in the brain, the diver can suffer a stroke or even die
Treatment involves the use of a hyperbaric chamber

73. Hyperbaric Chamber
The hyperbaric chamber increases the pressure on the diver’s body, allowing the nitrogen bubbles to re-dissolve
By slowly releasing the pressure, the nitrogen can safely leave the diver’s blood

74. 4.2 – Technologies Based on Flow Rates and Moving Fluids
Often we need to move fluids from one place to another
Both pumps and valves can be used to control where the fluid moves, and how quickly it moves

75. Pumps
Pump
Pumps can be found in many devices:

76. How a Bicycle Pump Works
Within a bicycle pump is a piston
As the piston is pushed down, it compresses the air inside the cylinder
This compressed air is forced out of a valve and through the hose (to an area of lower pressure)
Pull
Push

77. Pipeline Pigs
Pipeline pigs are computerized units that are used to clean and analyze oil and gas pipelines
These pigs are pushed though the pipelines by the pressure of the fluid within the pipeline

78. Valves Valves Valves come in a number of different shapes and sizes
Valves can even be found inside your body

79. Valve Types
Ball Valve
Butterfly Valve
Schrader Valve
Screw Valve

80. 4.3 – Submarines
Many parts of the ocean are too deep for humans to explore because of the pressure
Therefore, we have developed submarines and bathyscaphs (such as the Trieste) to explore the deep sea

81. How do Submarines Work?
Submarines change their depth by changing their density
They do this through the use of ballast tanks

82. As the submarine fills its ballast tanks with water, it becomes more dense than the surrounding water and sinks
To rise, the ballast tanks are emptied of water and filled with air, which makes the submarine less dense than the water around it

83. Robot Submarines
Robot submersibles (such as the Canadian ROPOS) can dive even deeper than manned submarines
This is because there is no easily-crushed pocket of air at the center of the submersible

84. End of Unit