Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
CC16H SC20H
Pearson GCSE Combined and Separate Chemistry Higher
| Question | Answer |
|---|---|
| What is a hydrocarbon? | A compound containing only hydrogen and carbon |
| Describe the nature of crude oil. | A thick brown liquid made of a mixture of many different hydrocarbons found in deposits underground |
| Describe the properties of the substances in crude oil. | Most of the hydrocarbons in crude oil are liquids, but each of them has a different boiling point |
| State the two most important uses of crude oil. | Fuel, feedstock (supply of basic chemicals) for the chemical industry |
| Crude oil is a finite resource. What does that mean? | There is a limited amount: at some point it will run out |
| What is fractional distillation? | A type of distillation used to separate mixtures of two or more liquids. It separates compounds according to their boiling point |
| Describe the 3 steps of fractional distillation. | "• Crude oil is passed through a heater to heat it to about 400OC so that nearly everything is a gas.• The hot gases rise up the fractionating column until cool enough to condense.• The separated liquids and gases collected at different temperatures |
| List the main fractions in order from those made up of the smallest molecules to the largest molecules. | Gases, petrol, kerosene, diesel oil, fuel oil, and bitumen |
| What is the viscosity of a liquid? | How easily a fluid flows –lower viscosity = runnier |
| How do the boiling point, viscosity and ease of ignition of the fractions of crude oil change as the molecules get larger? | Lowest to highest boiling point Lowest to highest viscosity Easiest to hardest ignition |
| What are the uses of Fuel Gases, Petrol, and Kerosene | Used for heating and cooking. Used as a fuel for cars. Fuel for aircraft |
| What are the uses of Diesel oil Fuel Oil Bitumen | Fuel for lorries and trains, Fuel for ships and power stations, Surfacing roads and roofs |
| What is a homologous series? | A group of closely related compounds with molecular formulae that differ only in the number of ‘CH2’s |
| What is an alkane? | A hydrocarbon with only single bonds |
| Name the first four alkanes and write their formula | Methane CH4, Ethane C2H6, Propane C3H8, Butane – C4H10 |
| How do boiling point, viscosity and flammability of alkanes change as their molecules get longer? | The longer the alkane the higher the boiling point, The longer the alkane the more viscous it is, The longer the alkane the less flammable it is |
| What is complete combustion? | Combustion that produces only water and carbon dioxide |
| What is incomplete combustion? | Combustion that produces carbon monoxide or carbon as well as carbon dioxide and water |
| Why does incomplete combustion occur? | When there is not enough oxygen for all of the reactants to be fully oxidised |
| How does carbon monoxide kill? | It sticks to haemoglobin in the blood which prevents it from carrying oxygen |
| What are the main problems caused by soot? | Causes lung problems when breathed in. Blackens and dirties buildings |
| What is acid rain? | Rain with a pH lower than 5.2 |
| Name three effects of acid rain. | Soil becomes too acidic for crops and plants to grow well • Acid in rivers and lakes prevents fish eggs from hatching and kills some insects. • Acid rain increases corrosion of limestone which damages buildings and statues |
| What are the products of cracking? | An alkane and a alkene |
| Why is cracking useful? | There is more demand for shorter hydrocarbons – such as petrol and gas – than longer ones such as bitumen |
| What is an alkene? | A hydrocarbon containing a C=C double bond. |
| What is crude oil? | A mixture of hydrocarbons |
| What is crude oil formed from? | The remains of ancient biomass (mostly plankton) that was buried in mud |
| What is a finite resource? Why is crude oil a finite resource? | One that will run out. Because it takes longer to form than the rate at which we are using it up |
| What is a hydrocarbon? | A compound made of atoms of carbon and hydrogen only |
| What is an alkane? | A hydrocarbon with only single bonds |
| Name the first four alkanes | Methane, ethane, propane, butane |
| What is the general formula for alkanes? | CnH2n+2 (the n and 2n are small) |
| How does boiling point change with the length of an alkane? | The longer the alkane, the higher its boiling point |
| How does viscosity change with the length of an alkane? | The longer the alkane, the more viscous (the thicker) it is |
| How does flammability change with the length of an alkane? | The longer the alkane, the less flammable it is |
| What is fractional distillation? | A process used to separate mixtures of substances with different boiling points |
| What are the steps involved in fractional distillation? | Crude oil is vaporised, different molecules rise up the fractionating column and cool down. Condense at different points on the column. |
| Why is fractional distillation important? | Because the different fractions have different uses |
| What is a fuel? | A substance which when reacted with oxygen releases energy |
| Name five fuels we obtain from crude oil | Petrol, diesel oil, kerosene, fuel oil and liquefied petroleum gases |
| What other uses are there for products of fractional distillation? | Solvents, lubricants, polymers and detergents |
| What is combustion? | The reaction of a fuel with oxygen |
| What are the products of complete combustion? | Carbon dioxide and water |
| When does incomplete combustion occur? | When there is not enough oxygen present |
| What is formed in incomplete combustion | Carbon monoxide |
| Why is carbon monoxide dangerous | It is toxic, taken up by red blood cells in preference to oxygen |
| What is cracking? | The process of breaking down a long hydrocarbon into smaller hydrocarbons |
| What are the products of cracking? | Short alkanes and alkenes |
| Why is cracking important? | Because smaller hydrocarbons are more useful than longer ones |
| What are alkenes | A hydrocarbon with a double bond |
| What are alkenes used for? | As a starting material to make more useful chemicals |
| What is the general formula for alkenes? | CnH2n |
| What are the first four alkenes? | Ethene, propene, butene, pentene |
| What do members of a homologous series have in common? | Same general formula, differ by CH2 for neighbouring compounds in the series, boiling points increase with chain length, have similar chemical properties and reactions |
| How is sulphur dioxide produced? | Sulphur impurities in fuels form it when the fuel is burnt |
| What happens when the sulphur dioxide dissolves in rain water? | Acid rain is formed |
| How are oxides of nitrogen formed? | When the nitrogen and oxygen in the air react together at the high temperatures created in combustion engines |
| State three advantages of hydrogen fuel cells over petrol | Do not need to be recharged, no pollutants are produced only H2O, water is a renewable resource |
| State three disadvantages of hydrogen fuel cells over petrol | Hydrogen is highly flammable, hydrogen is sometimes produced through non-renewable means, hydrogen is difficult to store and transport |
| What does finite mean? | It wil run out |
| How does ease of ignition change with the length of an alkane? | The longer the alkane, the harder it is to ignite |
| How are members of a homologous series different from each other? | Their chain length differs by a number of CH2 |
| Where do petrol, kerosene and diesel oil come from? | They are obtained by fractional distillation of crude oil |
| Where does methane come from? | It is found in natural gas |
| Are petrol, kerosene, diesel and methane renewable or non renewable? | non-renewable |
Created by:
Davenant Foundation School
Popular Chemistry sets