1. Unit 1: Mix and Flow of Matter Grade 8 Science Mr. Chin

2. WHMIS WHMIS: Workplace Hazardous Materials Information System

3. Topic 1: The States of Matter Solid: has definite shape and volume Particles in a solid are tightly packed together. The cannot move around freely, they can only vibrate. Examples??

4. Continued… Liquid: has a definite volume but no definite shape. Particles in a liquid have enough energy to slide past one another while they vibrate together in clusters. Examples??

5. Continued… Gas: has no definite shape or volume Enormous amounts of empty space between particles, they, like liquids will take the shape of their container. Examples??

6. Continued… Plasma: Makes up approximately 98% of the universe, however there is very little on earth. Plasma is a gas-like mixture of positively and negatively charged particles. Examples: lightning, auroras, neon signs

7. Particle Model of Matter The Five Main Points 1. All substances are made of matter 2. All particles in a pure substance are the same. Different pure substances are made of different particles. 3. Particles are always in motion. The speed of the particles increases when temperature increases. 4. Particles have space between them 5. There are attractive forces between particles

8. Changes of State

9. Topic 2: Mixing and Dissolving Classification of Matter

10. Pure Substances All pure substances contain only one type of particle. They can exist in three states of matter: solid, liquid and gas. Examples of Elements?? Examples of Compounds??

11. Mixtures Mixtures contain two or more pure substances Homogeneous Mixtures: Look as though they only have one substance. E.g. Kool-aid, Hot chocolate A homogeneous mixture where no settling occurs is called a solution

12. Mixtures Continued… Heterogeneous Mixtures: Mixtures that contain two or more parts that are still visible. Examples??

13. Mixtures Continued… In-Between Mixtures Suspension: A heterogeneous mixture in which the particles settle slowly. E.g. salad dressing Colloid: A heterogeneous mixture in which the particles do not settle. E.g. Smoke, dust Emulsion: A mixture in which droplets of fat are prevented from joining together by an emulsifying agent. E.g. Mayonnaise

14. Dissolving Dissolving: The complete intermingling of the particles of two or more substances. Solute: The substance that dissolves in the solvent to form a solution. There is usually less solute than solvent in a solution. Solvent: The substance that dissolves a solute to form a solution. There is usually more solvent than solute. You dissolve salt in water. Which is the solute?? Which is the solvent??

15. Continued…  Soluble: means able to dissolve in a particular solvent  Insoluble: means unable to dissolve in a particular solvent  Give an example of a substance that is soluble in water?  Give an example of a substance that is insoluble in water?

16. Factors That Affect Dissolving Agitation Solute Size Temperature Pressure Why do you think these factors can affect dissolving?

17. Solubility Solubility: The mass of a solute that can dissolve in a given amount of solvent to form a saturated solution at a given temperature. How much can be dissolved?? Saturated: No more solute will dissolve in a specific amount of solvent at a specific temperature. Supersaturated: A solution that contains more solute than would normally dissolve at a certain temperature.

18. Continued… SubstanceSolubility (g/100g Water) at 0oC0oC20 o C40 o C60 o C80 o C100 o C Copper Sulfate152030405579 Lithium Sulfate35 33313029 Ammonium Chloride 303845556578 1.Which substance has the greatest solubility at 80 o C? 2.Which solution is saturated at 60 o C, with 40g dissolved in 100g of water? 3.Mr. Chin wants to add 2g of Copper sulfate to a solution that already contains 14g of copper sulfate/ 100 g of water at 0 o C. What will happen??

19. Solubility

20. Topic 3: Viscosity & Density Viscosity: How thick or thin a liquid is. A thick liquid is more viscous and has a higher viscosity. Give examples of liquids with high viscosity. Give examples of liquids with low viscosity. Flow Rate: The time it takes for a liquid to flow from one point to another.

21. The Effect of Temperature on Viscosity of Liquids Warmer liquids flow quickly Cooler liquids flow slowly Examples?? Therefore…The viscosity of a liquid _________ as it is heated and _________ as it is cooled.

22. The Effect of Temperature on Viscosity of Gases Hotter air particles have more collisions than cooler ones. More collisions would cause them to move… Therefore… The viscosity of a gas _________ as it is heated, and _________ as it is cooled.

23. Density Density: Mass per unit volume of a substance. “Particle Crowdedness’’ Mass: The amount of matter in a substance (particles) Volume: Measurement of the space taken up by a substance Weight: Force of gravity on an object Force: A stress such as a push or pull What is the difference between weight and mass????

24. Formula for Density Density = Mass ÷ Volume D = M/V 1. Concentrated sugar could have a mass of 10g and take up a volume of 2cm 3. So the density would be… D = M/V ???

25. Density of Materials In general, gases are less dense than liquids and liquids are less dense than solids of the same substance. Explain… Does that mean all solids are more dense than all liquids? Can you think of any exceptions? How do you know??

26. Ice Crystals

27. Density FluidDensity (g/ml)SolidDensity (g/cm3) water1.00Cork0.24 seawater1.03Oak0.70 mercury13.55Sugar1.59 1.Which fluid has the lowest density? 2.Which fluid has the highest density? 3.Which solid would sink in seawater? 4.Which solid would sink in mercury?

28. Buoyancy Buoyancy: is the tendency for materials to rise or float in fluid. It is the ability of a fluid to support an object floating in or on the fluid. Average Density: The total mass of all substances on board divided by total volume. Even steel ships can float provided they have a hollow hull. It can be used to help floating objects sink too. A fish bladder enables a fish to increase or decrease their density by adding or removing air.

29. Average Density… Using the principle of Average Density explain how a Hot Air Balloon works…

30. Changes in Buoyancy Why is it so much easier to float in the Dead Sea than in any other ocean?

31. Archimedes’ Principle Archimedes was a Greek scientist around 212 BC. Archimedes Principle: The buoyant force acting on an object equals the weight (force of gravity) of the fluid displaced by the object! What does that mean??

32. Archimedes’ Principle Archimedes. Principle - states that: the buoyant force acting on an object equals the weight (force of gravity) of the fluid displaced by the object. - used his own body (which displaced water in the bathtub) to prove the king’s goldsmith was cheating the king - the buoyant force does not depend on the weight of the submerged object, but rather on the weight of the displaced fluid

33. Neutral Buoyancy If the water in a container is still, or at rest, then the water particles are neither rising nor sinking. An object immersed in a fluid such as water does not rise or sink if the amount of force pulling down (gravity) equals the amount of force pushing up (buoyancy). When gravity = buoyancy it’s called neutral buoyancy.

34. Question?? Why do you sink the bathtub but float in the ocean??

35. Pressure Pressure = Force ÷ Area P = F/A Force is measured in Newtons and area is usually measured in m 2. The unit for pressure therefore is N/m 2. This is also called a Pascal (Pa) for the man who invented it. A kilopascal equals???

36. Applications of Pressure Water hoses Fire extinguishers High heels! Cushioning materials All-terrain vehicles Other examples???

37. Compression of a Gas 1) The gas must be enclosed in a sealed container with sturdy walls 2) There is so much space between particles that even if they are squeezed together they will still behave as a gas 3) An external or outside force is applied to the enclosed gas to push the particles closer together. The great thing about applying force to a compressed gas is that there is a counter force which acts as a cushion. This is used in shocks and airbags in a car.

38. Balanced and Unbalanced Forces The Earth’s atmosphere is 160km thick and is held to the earth by gravity. The pressure of the weight of all that air is called atmospheric pressure. When you change altitude, you often feel a ‘pop’ in your ear – this is the pressure equalizing on either side of your eardrum. Balanced and Unbalanced Forces In a Container: Too much force inside, not enough outside = EXPLOSION Too much force outside, not enough inside = IMPLOSION

39. Technologies based on Solubility Separation Methods Desalination: Water is separated from a solvent via evaporation. The solvent (water) is recovered but the solute isn’t necessarily. Distillation: Boiling water allows it to be separated from a mixture and have each collected in different containers, leaving a distillate (water) and residue.

40. More Separation Methods Filtering: Materials are screened out leaving a filtrate and residue. Underground Solids: Material is crushed and dissolved, waste material is removed via a system of filters and the wanted mineral is left behind. E.g. Gold

41. Other Technologies Convenience foods are often dehydrated, so they can be stored for long periods of time without spoiling (you just add water when you want to use it)

42. Technologies Based on Viscosity and Flow Rate Lipstick: solvents, oils and waxes are mixed in such a way that their viscosity is increased so lipstick is solid. Gravy Paint Other examples???

43. Technologies for Moving Fluids Hydraulic Systems: Are devices that apply force/pressure to a liquid to move something else. E.g. water pump, oil and gas pipeline Pneumatic Systems: Are similar to hydraulic systems except gases are used instead of liquids. E.g. Dentist drill, jack hammer Compressor: A device that compresses air