Amy's Chemistry Blog: May 2011

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 odorless, colorless 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.