AQA GCSE Chemistry - Crude Oil Already Rated A+

AQA GCSE Chemistry - Crude Oil Already Rated A+ 1. What is crude oil, and what does it consist of? Answer: Crude oil is a mixture of a very large number of compounds, primarily consisting of hydrocarbons. 2. What is a characteristic of a mixture? Answer: A mixture contains two or more elements not chemically combined together, and the properties of the substances within a mixture remain unchanged. 3. What type of hydrocarbons dominate crude oil composition? Answer: Hydrocarbons, which are made up of hydrogen and carbon atoms. 4. What do saturated hydrocarbons contain? Answer: Saturated hydrocarbons, also known as alkanes, have no more atoms that can be added to the molecule. 5. How many single bonds can a carbon atom form before becoming saturated? Answer: A carbon atom can form four single bonds before becoming saturated. 6. What is the general formula for alkenes? Answer: The general formula for alkenes is C(n)H(2n+n). 7. What are the chemical symbols for methane, ethane, and propane? Answer: CH4, C2H6, and C3H8, respectively. 8. How can crude oil be separated? Answer: Crude oil can be separated through fractional distillation. 9. Why does distillation work? Answer: Different molecules have different boiling points, allowing them to be separated through distillation. 10. What is crude oil separated into during distillation? Answer: Crude oil is separated into fractions during distillation. 11. Which part of the distillation column is coolest? Answer: The top part of the distillation column is typically coolest. 12. Which hydrocarbons condense highest up the column? Answer: Those with the smallest molecules condense highest up the column. 13. Which fractions have the lowest boiling points? Answer: Those with the shortest chains have the lowest boiling points. 14. What happens to viscosity and flammability as chain length increases? Answer: As chain length increases, viscosity increases (becomes thicker) and flammability decreases. 15. What two elements do most fuels contain? Answer: Carbon and/or hydrogen, although they may also contain small amounts of sulfur. 16. What reaction occurs during combustion? Answer: The reaction between fuel and oxygen in the air produces oxides and releases energy. 17. What happens to elements in fuel during combustion? Answer: During combustion, the elements in the fuel are converted into their oxides. 18. What happens during the combustion of hydrocarbon fuels? Answer: Energy is released during the combustion of hydrocarbon fuels. What happens to carbon and hydrogen in fuels? (They are) oxidised What gasses are often released during complete combustion? Carbon dioxide, water vapour, sulphur dioxide, nitrogen oxide What gasses are often released during incomplete combustion? Carbon monoxide, water vapour, sulphur dioxide, nitrogen oxide, (particulates) What causes acid rain? Sulphur dioxide (and) nitrogen oxides