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Practical Data Analysis - Controlled Assessment. Objectives: Recall the steps in the Data Analysis assessment Understand the hypothesis (given by exam board) use science knowledge to explain the hypothesis
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Practical Data Analysis - Controlled Assessment • Objectives: • Recall the steps in the Data Analysis assessment • Understand the hypothesis (given by exam board) • use science knowledge to explain the hypothesis • relate the size of the forces between hydrocarbon molecules to the size of the molecules. What is a hypothesis? ................................ A hypothesis is a prediction, justified by a scientific explanation Read the OCR sheet carefully What is the hypothesis for this Data Analysis?
Hypothesis: Liquids containing long or large molecules are more viscous (ie they do not flow so freely) • In pairs, discuss then write down: • What is meant by viscous? • List 3 liquids in order, starting with the least viscous: • .................... • .................... • .................... (most viscous) • Why are some liquids more viscous than others? • Do you agree with the hypothesis? Why? • Use Revision Guide page 53 to write a paragraph, with diagrams, which explains (justifies) the hypothesis.
Hydrocarbon Molecules (from module C2) Hydrocarbons only have carbon and hydrogen atoms. These are all hydrocarbons but have very different properties: Butane (lighter fuel - gas) paraffin liquid candle wax poly(ethene) Match the pictures to the hydrocarbon name. Then explain the link between the length of the hydrocarbon molecule and its properties (state, boiling/melting point, viscosity)
Hydrocarbon Molecules - you learnt this in C2 Check your science explanation: • Longer chain molecules tend to become more tangled up, sticking to each other. • as the length of the carbon chain increases the area of contact between the different molecules i.........., thus attractions between the molecules increase and so the v.......... also increases • There are s.......... forces of attraction between the l.......... molecules so they are harder to separate than smaller hydrocarbons. • This means that small molecules are usually g..... while longer molecules are l........ and very long molecules are s........
Separation of Crude Oil depends on the different properties of the different molecules in crude. Which molecules are the most viscous?
These hydrocarbon molecules are identical except for the length of the molecule. Predict the order of their viscosity.