Chemistry C1 0.0 / 5 ? ChemistryCrude oil, cracking and hydrocarbonsGCSEOCR Created by: ikroliviaCreated on: 15-09-15 12:57 What are fossil fuels? Formed naturally over milions of years & are finite 1 of 24 What is a hydrocarbon? A molecule containing only hydrogen and carbon atoms 2 of 24 What is meant by cracking? Breaking down large alkane molecules into smaller, more useful alkane & alkene molecules 3 of 24 In hydrocarbons there are...? Strong covelant bonds & weak intermolecular forces 4 of 24 Complete combustion word equation methane + oxygen --> carbon dioxide + water 5 of 24 Incomplete combustion word equation methane + oxygen --> carbon monoxide + water 6 of 24 What are the percentages of gas in the air today? 78% nitrogen // 21% oxygen // 1% other gases 7 of 24 What does sulfur dioxide cause? Acid rain (kills plants & aquatic life and erodes stonework) 8 of 24 Are alkenes saturated or unsaturated? Unsaturated 9 of 24 How can you test for alkenes? Add bromine water. Alkenes decolourise bromine water & alKANES have no effect on it 10 of 24 What is Gore-Tex? A breathable material made from nylon. It allows sweat to escape whilst preventing rain from getting in. 11 of 24 What are emulsifiers used for? To get oil and water to mix (hydrophilic head & hydrophobic tail) 12 of 24 4 properties of Nylon lightweight / tough / waterproof / blocks UV 13 of 24 What are polymers? Plastics 14 of 24 What is the purpose of antioxidants? (food additives) They stop food reacting with atmospheric oxygen & increase shelf life 15 of 24 Why won't nail varnish dissolve in water? The attraction between water molecules is stronger than attraction between water molecules and nail varnish molecules 16 of 24 A perfume must smell nice, and must...? evaporate easily / not react with water / not dissolve in water / nontoxic / non-irritant 17 of 24 Pro & cons of animal testing Pro: no humans harmed // Cons: it's cruel & not same body chemisty 18 of 24 How do phosphorescent pigments glow? They absorb & store energy and then release it as light when dark 19 of 24 What can thermochromic pigments be used for? mood rings / bath toys / cutlery / to coat kettles to indicate temperature 20 of 24 Describe the 2 stages of how an oil-based paint dries 1) solvent evaporates 2) oil-binding medium reacts with o2 in air as it dries to form a hard layer 21 of 24 What is a binding medium? oil that sticks pigment to surface 22 of 24 What's a solvent? thins the thick binding medium & makes it easier to coat surface 23 of 24 Pigment Gives paint its colour 24 of 24
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