Group+4

=Grade 9 Chemistry : Chemical Reactions=

Title : Amount of hydrogen due to reaction between magnesium and hydrochloric acid
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Aim or Question
By the size of magnesium and concentration of hydrochloric acid, how much hydrogen gas will be produced in the same amount of time? Magnesium(s) + Hydrochloric acid(aq) -> Magnesium chloride(aq) + hydrogen (g) (Mg + 2HCl -> MgCl2 + H2)

Hypothesis
The less concentration of hydrochloric acid, the slower the mass will decrease, due to the collision theory. According to the collision theory, four factors that affect the speed of chemical reaction include the concentration. Therefore, as there are less concentration of hydrchloric acid, the speed of chemical reaction will decrease. Same for the size of magnesium, the four factors that affect the speed of chemical reaction also include surface area. Therefore, as there are more pieces of magnesium will increase the speed of chemical reaction. = = = = =Variables=

For experiment 1 Independent Variables: - Concentration of hydrochloric acid

Dependant Variables: - Mass of hydrogen produced

Constant Variables: - Same amount of time, same temperature, same volume of HCl, same surface area of magnesium.

For experiment 2 Independent Variables : - Surface area of magnesium

Dependant Variables : - Mass of hydrogen produced

Constant Variables : - Same amount of time, same temperature, same volume of HCl, same concentration of HCl. = = = = =Materials=
 * electronic balance
 * magnesium
 * hydrochloric acid
 * Stopwatch
 * water (in order to dilute copper sulphate)
 * three erlenmeyer flask

Process
1st experiment to test the concentration of hydrochloric acid. 2nd experiment to test different sizes of magnesium.
 * 1) Fill in 10ml of hydrochloric acid and 0ml of water into a flask. (Concentration of 1.0)
 * 2) Fill in 6ml of hydrochloric acid and 4ml of water into the other flask. (Concentration of 0.6)[[image:concentration1.JPG width="226" height="185" align="right"]]
 * 3) Fill in 2ml of hydrochloric acid and 8ml of water into the last flask. (Concentration of 0.2)
 * 4) Measure the mass of 2 magnesium and flask before the reaction by electronic balance.
 * 5) Put a flask on the electronic balance and put 2 magnesiums(1cm each) into the flask.
 * 6) Put the flask on the electronic balance and start recording the time as two pieces of magnesium is put into the flask.
 * 7) Record the amount of hydrogen produced by checking the decreased mass of the flask every 20 seconds and record in excel.
 * 8) To make sure the mass is exactly correct, have 1 person watch the timer and tell the person watching the mass to increase perfection.
 * 9) Repeat this process with three other flasks with a different concentration.
 * 1) Prepare three flasks with 10ml of same concentration (1.0) of hydrochloric acid.
 * 2) Measure the mass of magnesium and flask before the reaction by electronic balance.
 * 3) Put two, four, six pieces of magnesium (1cm each) into each flasks.
 * 4) Record the amount of hydrogen produced by checking the decreased mass of the flask every 20 seconds and record in excel.
 * 5) To make sure the mass is exactly correct, have 1 person watch the timer and tell the person watching the mass to increase perfection.
 * 6) Repeat this process with three other flasks with different number of magnesium pieces.

= = =Data Collection=

Table 1 : Concentration of hydrochloric acid vs amount of hydrogen produced.



Table 2 : Concentration 0.2 vs amount of hydrogen produced. Amount of magnesium vs amount of hydrogen produced.



Table 3 : Amount of magnesium vs amount of hydrogen produced.

= = =Data Processing:=

Figure 1 : Concentration of hydrochloric acid vs amount of hydrogen produced

Figure 1 : Amount of magnesium vs amount of hydrogen produced.



The amount of hydrogen produced is the (mass of magnesium + beaker + hydrochloric acid) - (mass of beaker + hydrchloric acid)

= = =Conclusion:=

Two experiments about the amount of hydrogen gas produced in the reaction between magnesium and hydrochloric acid was successfully done. Using the electronic balance, the amount of hydrogen was measured precisely. However, the results didn't turn out as how we expected.

For experiment 1

According to the first experiment, the 0.2 concentration would produce the most amount of hydrogen gas, 0.6 concentration would produce the least amount of hydrogen gas, and 1.0 concentration would produce the second most hydrogen gas.

The first experiment was changing the concentration of hydrochloric acid, that will react with the same amount of magnesium. The hypothesis was that concentration of 1.0 would produce the most amount of hydrogen gas, but it turned out to be not true. According to the collision theory, concentration is one of the four factors that affect the speed of a chemical reaction. In stronger concentration, there are more collisions between the reactants, the speed of reaction gets faster. However, due to mistakes made during the experiment, our result of the experiment does not match with the collision theory.

For experiment 2

According to the second experiment, the six pieces of magnesium produced the least amount of hydrogen gas. Two pieces of magnesium produced the second most hydrogen gas, and the 4 pieces of magnesium produced the most amount of hydrogen gas.

The second experiment was changing the numbers of magnesium. According to our hypothesis, the more amount of magnesium put into hydrochloric acid would mean more hydrogen acid produced. However, according to the collision theory, surface area is also one of the factors that affect the speed of reaction. As there are more collisions with larger surface area, the chemical reaction gets faster. But, same as the first experiment, due to several mistakes, the results does not match with the collision theory. = = = = =Evaluation:=

The experiment on the reaction between magnesium and hydrochloric acid seems to have some problem. The relationship between the magnesium and hydrochloric acid is not clear with the data, even though it can be proved by collision theory. There were two main problems in theexperiment. First of all, there were many mistakes about measuring the amount of hydrogen, due to careless preparation. Secondly, there are lack of images and videos that can enhance our Wikispace, which is also due to careless preparation. In conclusion, many mistakes could have been prevented by careful and pensive preparation, which is the most shameful part.

For further investigation, changing the temperature and finding out how it affects the speed of chemical reaction will be interesting. In addition, figuring out which factor most clearly affects the speed of chemical reaction will be a good experiment.

=Works Cited:=

Pictures: Electronic Balance-http://www.germes-online.com/catalog/17/20/780/page9/ Magnesium-http://www.superscienceproject.com/Magnesium_m.jpg Hydrochloric Acid-http://www.arikah.net/encyclopedia/images/d/da/Hydrochloric_acid_01.jpg Stopwatch-http://www.stopwatchesusa.com/images/products/EAI/40078-560_medium.jpg Water-http://watersecretsblog.com/archives/Image%2080%20tap%20water.jpg Erlenmeyer Flasks-http://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Erlenmeyer_flask_hg.jpg/450px-Erlenmeyer_flask_hg.jpg

Peer Review for Group 4 = = = =