Saturday, August 27, 2011

Producing alcohol by Fermentation and in Industry

FERMENTATION
Advantages

  • Raw material is renewable
  • Fermentation takes up little energy
  • It can transform food into a more stable form
Disadvantages:
  • Does not produce as much energy.
  • Very time consuming
  • Lots of workers are used to help the process.
IN INDUSTRY
Advantages:
  • Much faster than fermentation
  • One stage process
Disadvantages:

  • Non renewable
  • Could potentially be dangerous

Sunday, June 19, 2011

Alkanes

METHANE

ETHANE

PROPANE

BUTANE

PENTANE

3.4 I can recall the products of the complete and incomplete combustion of alkanes

   Saturated hydrocarbons are called alkanes
·         Small chain alkanes are used as fuels
3.       The reaction is called combustion
4.       The word equation for  this chemical reaction is :
fuel (methane) + oxygen carbon dioxide + water + ENERGY (heat, light, sound)
5.       If there is insufficient oxygen then the word equation is:
fuel (methane) + oxygencarbon monoxide + water + ENERGY (heat, light, sound)
6.       The problem with this reaction is that carbon monoxide is produced this gas is a poisonous gas to the human body (see objective 5.11)
7.       Where can you find incomplete combustion? In cars
8.       What is used to reduce the harmful products from incomplete combustion? 
9.       During incomplete combustion a smoky flame is often seen, explain this observation
10.   Describe the two chemical tests for water   blue anhydrous cobalt chloride turns pink
11.   Describe the chemical test for carbon dioxide gas lime water turns milky
12.   Describe a physical test for water- boiling point 100 Celsius
Extn: write a balanced equation (with state symbols) for the combustion of propane gas

Sunday, June 12, 2011

3.1 I can explain the terms homologous series, hydrocarbon, saturated, unsaturated, general formula and isomerism

Term
Definition
Example
Homologous series
 A family of compounds with the same general formula

 alkanes
Hydrocarbon
 a compound containing hydrogen and carbon
 Methane
Saturated hydrocarbon
the fact that each carbon has maximum number of bonds

ethane, propane
Unsaturated hydrocarbon
hydrocarbons which have double or triple covalent bonds.

butane
General formula
 A mathematical formula to show how many carbons and hydrogens there are in the homologous series. 

 CnH2n+2


Isomerism



Sunday, May 22, 2011

5.13 I can describe catalytic cracking of long chain hydrocarbons






1.How are long chain hydrocarbons broken down?
By using heat.


2. What is the main safety aspect of the experiment? 
As the experiment goes on, you should not allow the water to go back to the test tube, as it will hit the steam and may cause an explosion.


3. What is cracking?
When long chain hydrocarbons are broken down, into smaller chains by using heat.. 


4. Why does the rate of gas production increase as the experiment goes on?
Because when the hydrocarbons get heated, the experiment moves faster.


5. Why does the ceramic pot turn black?
Because of interaction with organic material


6. What is the ceramic pot used for?
They are used as a catalyst to speed up the experiment


7. Why is the gas collected over water?
Because the gas is less dense than air, so then it goes into the test tube.


8. Why is cracking useful?
Because short chain hydrocarbons are more useful than long chain hydrocarbons.

Friday, May 20, 2011

5.12 I can recall the problems associated with fractional distillation of crude oil.

a. When crude oil undergoes Fractional Distillation there are too many large chain hydrocarbons e.g. (bitumen) produced and not enough small chain hydrocarbons e.g. petrol 


b. To solve these problems large chain hydrocarbons undergo a chemical reaction called Cracking..

5.11 I can recall how nitrogen oxides are formed in car engines





a.       Write the general equation for the combustion of a fuel
fuel + oxygen ------> carbon dioxide +water+energy 
b.      During combustion the nitrogen in air can react to form what gases?
nitrogen monoxide, nitrogen dioxide
c.       What condition is necessary for this reaction to take place?
high temperatures
d.      In what common object is this condition found?
Cars
e.      Why is this condition needed for nitrogen to react?
Because nitrogen has a very strong covalent bond.
f.        What are the dangers of the products from this reaction?
When the products dissolve into water, they produce nitric acid which contributes to acid rain, which then erodes limestone buildings

5.10 I can recall the problems associated with incomplete combustion






2.       What are the properties of carbon monoxide?
Carbon Monoxide is odorlesscolorless and is an extremely toxic gas.
3.       Explain how carbon monoxide is formed
Carbon Monoxide is formed when there is incomplete combustion, and there is not enough oxygen to make carbon dioxide.
4.       Explain why carbon monoxide is poisonous
It is poisonous because, when it is breathed in, the carbon monoxide sticks to the hemoglobin easier than oxygen does. THe hemoglobin then has trouble carrying oxygen around the body. 

5.9 I can describe the trend in boiling point and viscosity of the main fractions




a.       What is the trend in boiling point of the fractions?
The higher the fractions in the column the lower the boiling point
b.      Define viscosity (source your definition)
The state of being thick. source (
c.     What is the trend in viscosity of the fractions?
As you go up the column, the viscosity increases
d.      What is the trend in colour of the fractions?
The lower in the Fractionating column, the thicker and darker the colour gets.
e.      Why is crude oil separated into fractions?
So it can be useful to people in the world.
f.        What process is used to separate crude oil into fractions?
The fractionating column is used with different temperatures
g.       What physical property allows this process to work?
Different boiling points 


So it can be useful to people in daily life.

Thursday, April 28, 2011

5.6 I can recall what crude oil is made from.

a. Define the word hydrocarbon?
 A hydrocarbon is a  compound containing only hydrogen and carbon
b. Crude oil is a _mixture__ of _many hydrocarbons_


c. What is crude oil made from?
 Crude oil is made from tiny animals and plants that lived in the sea.
d. How long does it take to make?
 Millions of years
e. Where does the energy originally come from?
 The sun
f. How is crude oil different from coal?
 Coal is not a hydrocarbon.
g. Crude oil, coal and natural gas are collectively known as _fossil fuels

h. How is crude oil transported when it is extracted from the ground?
 By pipeline or oil tanker