C9- crude oil and hydrocarbons ⛽️ Flashcards
What is crude oil ?
- crude oil is a molecule of hydrocarbons, that was formed over millions of years, from the remains of ancient dead marine organisms.
Where is crude oil found ?
- found in rocks, crude oil is a finite resource [meaning crude oil is used up at a faster rate, than it can be replaced]
How is crude oil formed ?
Hint: remains
- crude oil is formed over millions of years, from the remains of tiny sea creatures called plankton- which were buried in mud
What are hydrocarbons ?
Hint: molecules
- hydrocarbons, are molecules made up of hydrogen and carbon atoms only
What’s an alkane ?
- an alkane, is a saturated hydrocarbon with the general formula CnH2n+2
What’s the general formula of alkanes ?
- CnH2n+2
- [you have to multiply the number of carbon atoms by two, and then add two]
How can the general formula of alkanes be used ?
Hint: multiply
- if the number of carbon atoms (n) is known, the number of hydrogen atoms can be calculated
- this is done, by multiplying the number of carbon atoms by 2 and then adding 2
What is the structure of methane ?
- CH4 [methane has one carbon atom and four atoms of hydrogen]
What is the structure of ethane ?
- C2 H6 [ethane has two carbon atoms, and six hydrogen atoms]
What is the structure of propane ?
- C3 H8 [propane has three carbon atoms, and eight hydrogen atoms]
What is the structure of butane ?
- C4 H10 [butane has four carbon atoms, and ten hydrogen atoms]
What does it mean, that alkanes are saturated molecules ?
Hint: fully
- alkanes are saturated molecules because in alkanes, the carbon atoms are fully bonded to the hydrogen atoms
What are examples where hydrocarbons, are used as fuels ?
- an example where hydrocarbons, are used as fuels are:
- ships, planes and cars
What do hydrocarbons do, when they combust ?
- hydrocarbon fuels, release energy when combusted [burned].
What happens during the combustion of hydrocarbons ?
Hint: OIL RIG
- during combustion, the carbon and hydrogen atoms in the fuel will react with oxygen as become oxidised [the loss of electrons; the gain of oxygen]
What products are formed, during complete combustion of a hydrocarbon ?
Hint: unlimited
- if the oxygen that the carbon and hydrogen atoms react with are unlimited, this reaction produces carbon dioxide and water.
- this is because, the hydrocarbons completely combust
What are the three key properties of hydrocarbons ?
- viscosity- meaning the thickness of a fluid
- flammability- meaning, how easily a hydrocarbon combusts [burns]
- and, boiling points- the temperature at which a liquid turns to a gas
What is viscosity ?
- viscosity, is the thickness of a fluid. [the resistance of a fluid to flow]
- fluids with a high viscosity will flow slowly
- ; as the size of the hydrocarbon molecules increase, the molecules get more viscous.
Fill in the gaps: because hydrocarbon molecules get more _______, if the size of hydrocarbon molecules increase, ____ chain hydrocarbons such as butane are extremely viscous.
- because hydrocarbon molecules get more viscous, if the size of hydrocarbon molecules increase, long chain hydrocarbons such as butane are extremely viscous.
What are the flammability of hydrocarbons ?
- short-chain hydrocarbons such as methane are extremely flammable
- this is because, as the size of the hydrocarbon molecules increases, the molecules get less flammable
- ; long chain hydrocarbons such as butane, are very difficult to burn.
What are the boiling points of hydrocarbons ?
- as the size of the hydrocarbon molecules increases, the boiling point also increases
- this means, very long chain hydrocarbons such as butane, have very high boiling points
Why does the boiling point of hydrocarbons increase if the size of the hydrocarbon molecules increase ?
Hint: atoms and electrons
- because, the intermolecular forces bewteen alkanes become more significant, as the number of atoms and electrons in a molecule increase
