Chrmistry Paper 2 Flashcards
What is cracking?
Cracking is taking longer chain hydrocarbons molecules and breaking them down into smaller more useful molecules.
What is the general formula for alkenes?
CnH2n
What is the general formula for alkanes?
CnH2n+2
What are the first 5 alkanes?
Methane, ethane, propane, butane and pentane.
What is crude oil?
Crude oil is a mixture.
How is crude oil formed?
Formed over millions and millions of years from the remains of Dead Sea creatures.
What is a finite resource?
A resource in limited quantities.
How can you identify an impure substance?
An impure substance has a lower melting point and melts over a temperature change.
What is the common trend in impure substances?
Impurities tend to lower the melting point and increase the boiling point.
What is a pure substance?
A single element or compound not mixed with any other substances.
What are the requirements for cracking?
Cracking requires high temperatures and a catalyst.
What is membrane distillation?
Salt water is forced through the membrane sheets at high pressure. Membrane sheets are designed to catch salt ions/ bigger molecules. Water can pass through the membrane but sodium and chlorine can’t.
What is desalination?
A process that removes minerals from saline water.
What is distillation?
The process if separation of a mixture through selective evaporation. But it requires a lot of energy and is expensive.
What is drinking water?
Also known as potable water is water that is safe to drink or to use in food preparation without risk of acute or chronic health impacts.
What is pure water?
Also known as purified water is water from a source that has removed all impurities and is fit to drink. Distilled water is the most common form of pure water.
What is the simple rule for bonding?
Non metal + non metal = Covalent
Metal + non metal = Ionic
Metal + metal = Metallic
What way will the equilibrium shift if the temperature is increased.
The equilibrium will shift in favour of the reaction.
What way will the equilibrium shift if pressure is increased?
If pressure is increased the equilibrium will shift in favour of the reaction. So whatever side has less gas molecules is favoured. If the pressure is the same on both sides there’ll be no reaction.
What happens if there isn’t enough air for incomplete combustion?
Then incomplete combustion occurs forming carbon monoxide.
Why is carbon monoxide poisonous?
Carbon monoxide is toxic because it combines with haemoglobin in the blood to reduce capacity of the red blood cells carrying oxygen.
