Check & Reflect Answers

2. Check & Reflect Answers 1. Sketch should be similar to Fig 2.13 c) on page 35. Solute particles (coffee) and the solvent particles (water) and arrows of motion should be used 2. Factors that speed up the rate of dissolving are stirring, breakup up the solute, and increasing the temperature.

3. AYL 1. Sugar, salt, water, gold are examples. A pure substance is made of all the same particles and cannot be separated 3 In paper chromatography, the substance being tested is the solute 4 As the temperature increases, the particles of solute and solvent move faster, so they bump into each other more quickly. This increases the rate of dissolving 5 If paint was spilled on the floor, a liquid that could dissolve paint would have to be used. For latex paint, the solvent could be water. For oil-based paint, a solvent such as acetone could be used. Focus on Science and Technology # 1 You need to know the differences between pure substances and solutions

4. Which of the following is not true about the particle model of matter? All substances are made of tiny particles. All particles in a pure substance are the same. The particles have spaces between them The particles are not in movement.

5. Copy This Down Viscosity and the Effects of Temperature Section 3.1 Confucius say: Man who want pretty nurse, must be patient.

6. Quick Demo……Be Open-Minded! Air bubble in: • Water • Dish soap • Corn syrup • Why does the bubbles travel at different rates?

7. Copy This Down Definition • Viscosity – liquid’s internal resistance or friction that keeps it from flowing. • How does this happen? Particle theory explains that the particles in a liquid slide around each other. In gas, they move more easily. • The greater the friction or rubbing between particles in any fluid, the higher the viscosity. • Fluids with high viscosity do not flow as easily as fluids with low viscosity.

8. Viscosity Demo Pudding & Milk (how about with 2 different size straws?)

10. Recall: • What are 3 factors that affect solubility? • What are 3 factors that affect rate of dissolving? • What is a common theme between both??

11. Copy This Down Understanding Viscosity and Temperature • As the temperature of a liquid increases, its viscosity decreases. (ie. flows faster) • As the temperature of a liquid decreases, its viscosity increases. (ie. flows slower) • Particles can slide more quickly when there is extra energy from heat.

12. Copy This Down Measuring Viscosity • Ramp method • Pouring a fluid down a ramp and time how long it takes to get to the bottom • Able to test different fluids, or same fluids at different temperature, or both! • Demo: dish soap! • Able to calculate flow rate after (next slide)

13. Copy This Down Flow Rate How fast a fluid moves Flow Rate= volume/ time Usually ml/ second

14. Different Fluids Have Different Viscosities. We use them different ways based on their viscous properties. a) Motor Oil is used as a lubricant in engines at different temperatures in different regions and in different seasons of the year. b) Fluids are moved across the country through pipelines. Heaters are used to control viscosity along the length of the pipeline. c) Extraction of oil - (Alberta Oil Sands) Only 25% can be extracted by conventional methods, whereas, 75% can be extracted by lowering the viscosity of the oil in the ground, before trying to extract it. d) Cleaning: products that can have their viscosity adjusted by changing the temperature (e.g. to remove bubble gum from a shoe or carpet, lower the temperature by using an ice cube, to make the bubble gum more viscous, then it will be easier to remove)

15. Homework! • P. 41 Check & Reflect • 2 • 3 • 4 • 5 Please print off ‘Density Worksheet’

16. Lab Time! • Viscosity lab • Formal lab report example