Fuels Flashcards
What are hydrocarbons?
Compounds that contain carbon and hydrogen only.
What is crude oil?
A complex mixture of hydrocarbons, containing carbon atoms in chains or rings. It’s an important source of useful substances and a finite resource.
How is crude oil separated into useful mixtures?
Through fractional distillation, where crude oil is heated and hydrocarbons separate based on their boiling points.
Name the main fractions of crude oil and their uses.
Gases: domestic heating and cooking
Petrol: fuel for cars
Kerosene: fuel for aircraft
Diesel: fuel for cars and trains
Fuel oil: ships and power stations
Bitumen: roads and roofs
How do hydrocarbons differ in different fractions?
They vary in number of carbon/hydrogen atoms, boiling points, ease of ignition, and viscosity. Smaller molecules are less viscous, have lower boiling points, and ignite more easily.
What is a homologous series?
A series of compounds that have the same general formula, differ by CH₂ between compounds, show gradual variation in physical properties, and have similar chemical properties.
What are the products of the complete combustion of hydrocarbons?
Carbon dioxide (CO₂), water (H₂O), and energy (exothermic reaction).
Why is carbon monoxide dangerous?
It is a toxic, colorless, and odorless gas that prevents red blood cells from carrying oxygen, leading to death.
What can be produced by the incomplete combustion of hydrocarbons?
Carbon (soot) and carbon monoxide (CO) due to insufficient oxygen.
What are the problems caused by incomplete combustion?
Carbon monoxide causes health problems, and soot contributes to global dimming.
How does sulfur dioxide form and what problems does it cause?
It forms when sulfur in fuels reacts with oxygen. It can cause acid rain, damaging buildings, trees, and aquatic life.
What are nitrogen oxides, and how do they form?
Nitrogen oxides are pollutants formed when nitrogen and oxygen react at high temperatures in engines. These include nitrogen monoxide and nitrogen dioxide.
What are the advantages and disadvantages of using hydrogen as a fuel?
Advantages: Only produces water, does not emit CO₂.
Disadvantages: Expensive, difficult to store, and potentially dangerous (explosive).
What are non-renewable fossil fuels obtained from crude oil?
Petrol, kerosene, and diesel. Methane is also a non-renewable fossil fuel found in natural gas.
What is cracking and why is it necessary?
Cracking breaks down larger hydrocarbons into smaller, more useful ones. It’s necessary because there is higher demand for smaller, more easily ignited hydrocarbons.
