Sunday, December 09, 2007

The Special Ones.

Hover your mouse over the pictures of some of my favourite people/characters currently for my commentary on why I love 'em so.

Cassie from Skins, a hyper little anorexic, but the kindest person ever. I adore her, and was sooooo pleased when she and Sid got together.Blake Lively, she's got style.Lizzie Bennet, she's extremely sharp and witty, and really cares about those around her. Can be a bit stubborn, but will find Mr. Perfect eventually. Lovely!Holly Golightly, Audrey rocks.Saoirse Ronan, her performance in Atonement was terrific and I can't wait for her performance in The Lovely Bones..Fernando Torres, his freckles tease me endlessly. Muy caliente!


Anonymous said...

Cassie - yes
Saoirse - yes
Torres - YES!!!!!!!!!

He scored against you.

Emma said...

Yes, I know.

He won't scored against Utd this weekend. He and Cristiano will go missing.

Anonymous said...

Nah, he'll be instrumental in our 7-0 win.

Chelsea, on the other hand, will lose to Arse

Emma said...

Cristiano will go missing. Nando Torres will go missing. Jamie Carragher will score an own goal. Steven Gerrard will dive to win a penalty, which he'll score. 1-1.

12-0 to Chelsea, obvs.

Anonymous said...

Investigation of the factors affecting the rate of reaction between magnesium and hydrochloric acid

Background Knowledge
- The balanced equation for the reaction between hydrochloric acid and magnesium is:
Magnesium + Hydrochloric acid à Magnesium chloride + Hydrogen
Mg(s) + 2HCl (aq) à MgCl2 (aq) + H2 (g)

When this reaction takes place, the magnesium begins to give off hydrogen gas as bubbles (effervescence). When the solid magnesium disappears and there is no more effervescence, the reaction is complete.

· The rate of a reaction is the speed of the reaction - how quickly a reaction takes place.. It can be measured as the rate of formation of product, such as collecting gaseous product or the rate of disappearance of reactant, such as the disappearance of magnesium.
· Particles have a wide range of kinetic energy but only a small fraction have enough kinetic energy to break bonds and bring about chemical change so as a result most collisions are not successful.

- For a reaction to take place, the particles of the substances that are reacting have to collide. If they collide, with enough energy then they will react. The minimum amount of kinetic (movement) energy that two particles need if they are going to react when they collide is called the activation energy.
- Chemical reactions happen when reacting particles collide with enough energy to break bonds. The rate of reaction is speeded up when there are more reactions, or if the collisions happen with more energy.
- Temperature, concentration, pressure of gases, sizes of solid reactants and catalysts are all factors affecting rate of reaction.
- A catalyst is a chemical which is used to speed up the rate of a reaction, but it itself is not changed chemically.

I will fill a burette with distilled water and attach it to a clamp and stand. I will fill an old ice cream tub about ¾ of the way with water. Using beakers of solutions of chosen concentration of hydrochloric acid, I will attach it to a burette to a conical flask via a delivery tube. Before I add the magnesium strip to the hydrochloric acid solution, I will measure the level of water on the burette. Then I will add the 5 cm magnesium strip, put a bung over the conical flask and start the timer immediately. I will take readings of the level of water at the burette every 10 seconds and stop when the hydrogen has displaced the water completely.


To make different concentrations of hydrochloric acid, I will mix a 2M hydrochloric acid solution with distilled water in these ratios:
Concentration (M) Volume of 2M HCl (cm ) Volume of water (cm )
0.2 5 45
0.4 10 40
0.6 15 35
0.8 20 30
1.0 25 25
1.2 30 20
1.4 35 15
1.6 40 10
1.8 45 5
2.0 50 0

For the actual experiment I will only take 5 or 6 values from these, the concentrations I will select will depend on the results from the preliminary experiment.

I will repeat the experiment with the different concentrations. I will then repeat them for more reliable results.

Apparatus and chemicals used
- Beakers
- 2M Hydrochloric acid
- Distilled water
- Measuring cylinder
- Burette
- Conical flask
- Bung
- Delivery tube
- Ice cream tub
- Ruler
- Magnesium strips
- Scissors

Factors that affect the rate of reaction

Factor Reason for its effect How it will be controlled
Size of reacting particles If one of the reactants is a solid, the rate of reaction will be faster is the same amount of solids is faster when there is a larger surface area. Reducing the size of particles increases the rate of a reaction because it increases the surface area available for collisions to take place. This increases the number of collisions. It has no effect on the energy of the particles. The more magnesium there is, the longer the reaction will take. The same length of magnesium will be used through.
Temperature if the temperature is raised, particles have more energy so there will be more successful collisions, and particles will also move faster so there are more collisions. The entire experiment will be carried out at room temperature.
Presence of a catalyst A catalyst lowers the activation energy so the particles can react with less energy than they needed before the catalyst was added. With a catalyst, the experiment would occur in less time. No catalyst will be used throughout the experiment.
Magnesium strip There may be a thin layer of oxygen on the magnesium strip, this could react with the HCl instead of magnesium. I will wipe the magnesium strip clean before the experiment.

Key Factor that I shall Vary
The concentration of the solution.

Hydrochloric acid is a corrosive and irritant so students should take extra care when carrying out the experiment. When cutting the lengths of magnesium students should be careful with scissors as well as the

I will measure the amount of water displaced by the hydrogen, so I will measuring the appearance of a product from the reaction. I will take my results to the nearest 0.1 of a cm. I will take the measurement of water displaced every 5 seconds.
I will take 5 lots of repeats so my results will be as consistent as possible.

I predict that the higher the concentration of hydrochloric acid, the faster the reaction. In a 2M HCl solution, I predict that the length of magnesium strip will react completely in a few seconds, and in an 0.2M HCl solution, it will take a very long time to react. This is the trend in the preliminary trial. This will be because in concentrated solution there is a higher chance of particles hitting each other. When the HCl solution is less concentrated, reactions will be slower because there are less reacting particles in the same volume of solution.
I predict that when the concentration is twice as concentrated, the rate of reaction will be twice as fast. This is because there will be twice as many reacting particles in the same volume of solution, so twice as much collisions should occur.

Making sure my evidence is precise and reliable
For precise results I will read the levels on the burette to the nearest 0.1cm³. For reliable results I will repeat the experiment two more times, then take an average of the three readings. If there are any clear anomalies, I may retake the result.

Preliminary Work
A previous experiment had been done before with the same aims.

Average water displaced (cm³)Time seconds
Moles 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45 50 55 60
0.4 0.0 0.0 0.0 0.0 1.0 3.2 9.4 15.8 17.6 22.2 24.2 24.2 24.2

0.6 0.0 0.2 5.7 6.7 12.9 17.9 19.5 19.5 19.5 19.5 19.5 19.5 19.5

0.8 0.0 2.4 9.6 20.8 23.2 27.8 27.9 27.9 27.9 27.9 27.9 27.9 27.9

1.0 0.0 1.9 7.9 19.5 28.1 26.8 26.8 26.8 26.8 26.8 26.8 26.8 26.8

1.2 0.0 0.2 16.3 33.9 37.2 37.2 37.2 37.2 37.2 37.2 37.2 37.2 37.2

1.4 0.0 35.8 36.5 36.5 36.5 36.5 36.5 36.5 36.5 36.5 36.5 36.5 36.5

1.6 0.0 0.2 28.9 40.9 40.9 40.9 40.9 40.9 40.9 40.9 40.9 40.9 40.9

1.8 0.0 20.0 43.1 43.1 43.1 43.1 43.1 43.1 43.1 43.1 43.1 43.1 43.1

2.0 0.0 26.9 49.9 50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0

This was not a very successful experiment. Although I achieved results, I didn’t carry out enough repeats to be completely sure that the results were reliable.

For the real experiment, I will take repeats. In this experiment I didn’t take any, therefore if there were any anomalous results, I would not be able to tell which one it was. Having more results also makes the experiment more reliable, as different values are involved in calculating average.

It had taken too long for the solutions of 0.2M, 0.4M (unrecordable) 0.6M to turn react with the magnesium. I will definitely not use these values for the real experiment.

The 1.8M and 2.0M solutions were too quick at reacting and it is likely that the time measured was not precise.

For the experiment the range of values I will use will be: 0.8M, 1.0M, 1.2M, 1.4M, 1.6M, and 1.8M.

Carla said...

Nice. Chemistry.

Btw, I checked out some of that Jose Vanders girl who goes to your school.

Don't know what you made such a fuss about tbh. She sounds like a 5-year-old.

Emma said...

That is so unbelievably harsh and rude! Have you heard "Ode to Gilbert"? One of the most moving songs ever.