Answers

Here are the answers to the questions as promised. Now correct the work that you blogged. Two options to do this:

1. Send another e-mail to your blog called “Corrections to…” and highlight the changes in a different colour.

2. Edit your blog post and make the changes in a different colour.

Cheers,

Mr B

5.9 and 5.10 answers

28 October 2011

10:21
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5.7 and 5.8 Starter answers

28 October 2011

11:00
· What are the 6 processes shown by the arrows?

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Melting

Boiling

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5.7 and 5.8 Answers

28 October 2011

10:20
· Collins p.112
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1a
· Particles in a solid are strongly bonded to each other so their particles are held in a fixed, regular pattern and can not move
· The bonds between particles in liquids and gases are weaker and therefore their particles can move relative to each other

1b
· The particles in solids and liquids are closely packed and they are therefore incompressible
· The particles in a gas are very widely spaced and the forces between them are very weak so they can spread out to fill their container
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Boiling
· Boiling occurs when you heat a liquid until the average energy of the particles is great enough for them to turn into a gas
· Boiling occurs at a fixed temperature called the boiling point
· Boiling occurs throughout a liquid
· It is a fast process
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Evaporation
· Evaporation occurs when a liquid is left open to the air
· Only particles at the surface of the liquid that have enough energy can escape the liquid into the air
· Evaporation occurs for a range of temperatures; high temperatures increase evaporation, low temperatures decrease evaporation
· Evaporation only occurs from the surface of a liquid
· It is a slower process
· Because it removes the most energetic particles from a liquid the average energy of the remaining particles is decreased and the liquid cools down
· [cid:image007.png@01CC9575.884BC100]

See the full gallery on Posterous

Game

Click to play

Click to Run

5.7 and 5.8

· What are the 6 processes shown by the arrows?
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Solid --> Liquid: Melting
Liquid --> Gas: Boiling
Gas --> Liquid: Condensing
Liquid --> Solid: Freezing
Solid --> Gas: Desublimation/ Deposition
Gas --> Solid: Sublimation

5.7 and 5.8

· 5.7 understand that a substance can change state from solid to liquid by the process of melting
· 5.8 understand that a substance can change state from liquid to gas by the process of evaporation or boiling
· Questions from Collins p.112
· Answer in Bullet Points!

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· Use following pages from Collins as a resource to help you

Q1 a) -Particles in solids are stronger and fixed together
-Gases and liquids have a weaker bond between particles
b) -The particles in liquids and solids are closer together and more compact than the particles in a gas
-The particles in gases are weak so they can move around freely and spread out to fill their container

Q3)
Boiling=
-Done by humans and the liquid needs to be heated up to their boiling point
-Boiling happens quickly
-Boiling occurs throughout a liquid

Evaporation=
-Evaporation happens naturally when a liquid is left in the open air
-Only the particles on top evaporate because they have enough energy
-Evaporation doesnt need a fixed temperature (liquid doesnt need a boiling point)
-It is a slow process
-Because it removes the most energetic particles from a liquid the average energy of the remaining particles is decreased and the liquid cools down

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5.7 and 5.8 Experiment - Cooling Curve of Stearic Acid using datalogger

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states of matter drag and drop plenary.swf Download this file

Fill the trucks - Properties of s,l,g.swf Download this file

5.9 and 5.10 starter

· 5.9 recall that particles in a liquid have a random motion within a close-packed irregular structure
· 5.10 recall that particles in a solid vibrate about fixed positions within a close-packed regular structure
· Complete the missing words in the table below
· Cut and paste the particle images into the table

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State

Particle

Picture

Arrangement of Particles

Motion of Particles

Other Properties

Solid:
· closely packed
· regular pattern

· vibrate about a fixed position

· fixed shape
· not easily compressed since particles are closely packed
· Strong bonds

Liquid:
· closely packed
· no pattern

· free to flow over each other

· takes shape of its container
· can be poured
· not easily comressed since particles are closely packed
· Weak bonds

Gas:
· widely spaced
· no pattern

· very fast moving
· random directions

· fills its container
· can be poured
· easily compressed since its particles are far apart
· Very weak bonds

s,l,g animation.swf Download this file

See the full gallery on Posterous

5.6 Questions

Collins, p.107

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Note: ρfresh water = 1,000kg/m3; g = 10N/kg
Q5=
change in p = h x p x g
250000-100000= h x 1000 x 10
h = 150000 / (1000 x 10)
h=15m

Q6=
?

5.6 Demo - squirting water column

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· The bottom hole squirts water the furthest
· Because the water at the bottom has the greatest pressure
· Because in the formula ∆p = h × ρ × g, ρ is constant, g is constant and h is large
· So ∆p = large

5.6

· 5.6 recall and use the relationship for pressure difference:

pressure difference = height × density × g
∆p = h × ρ × g

∆p = pressure of the fluid (N/m2 or Pa)
h = height of the fluid (m)
ρ = density of the fluid (kg/m3)
g = gravitational field strength (N/kg)