Delivery tube for conical flask with side arm Electronic weighing scales Apparatus setup and procedure Measure out the required concentration in ratio with water with 50ml of solution. Once you have measured these concentrations in to your 5 measuring cylinders, fill your 200ml measuring cylinder with water completely so that there are NO air bubbles left in the top; and invert it into your tub of water fixed by the clamp stand. Measure out the Magnesium strips to 0. 1g exactly and place it into the conical flask before pouring the concentration of Sulphuric acid to the solution.
Now place your conical flask with side arm with the 1g of magnisium inside and clamp it to a clamp stand and feed the side arm into the water and positions it so the end of the funnel is inside the 200ml measuring cylinder once again ensuring no air bubbles are released into the measuring cylinder prior to the experiment.. Draw up some rough results tables and make sure before starting the experiment to have someone to record the results with a stopwatch, someone to observe the experiment and to call out the results shown, also someone will have to put the solution of H2SO4 and H20 into the conical flask and place the bung.
Once all is ready place the H2SO4 solution in the conical flask with the magnisium and place the bung on immediately, record the results shown every 5 seconds for 40 seconds. Repeat each concentration 3 times. Making sure that all the Hydrogen bubbles are released into the measuring cylinder and not the tub to obtain the most accurate results as possible.
Variables: Concentration of the Sulphuric acid solution: As the concentration gets higher, the more lightly particle collision is going to occur simply because there are more of them.
Gas released: Hydrogen Constants: 0. 1g of magnesium Magnesium ribbon (Low surface area): The smaller the piece of magnesium e. g. powder; the larger the surface area. The larger the surface are; the faster the rate of reaction. With a higher concentration of Sulphuric acid, a high surface area would make the reaction to fast to be monitored accurately so ribbon is being used. 50ml sulphuric acid Constant temperature: The temperature will be kept as constant as possible considering the experiment location.
This is to keep my results as accurate as possible, the higher the temperature the more energy the particles carry making them move a lot faster in their container; This faster movement causes collision of particles to occur more frequently, increasing the rate of reaction. Intervals between recording results: 5 seconds Fair test: In order to see that this experiment is a fair test the ‘constant’ factors shown above will have to remain so. If they are not the experiment will be more prone to anomalies. As well as this the other factors that can affect the rate of reaction must be kept constant.
These are surface area, temperature, and a catalyst. I will also have to make sure the cork and the side arm are firmly put in their positions to ensure that all the hydrogen released from the reaction is collected in to the large measuring cylinder. Preliminary Trials: Before starting the main experiment I carried out a set of preliminary trials to ensure all the correct equipment and the right concentrations and amount of solutions where selected for the main experiment. The areas that where needed to be decided upon where the surface area of magnisium.
The amount of the Sulphuric acid solution that was to be used. The mass of magnisium to use in the experiment. The initial choices and there changes are shown here: 1. The surface area: Was originally powder form Changed to ribbon form, because of the reaction was too fast to monitor with the higher concentrations of sulphuric acid. 2. The amount of sulphuric solution used: Was originally 50ml sulphuric solution Now changed to 20ml because the 50ml was too much for 0. 1g of magnisium to react with. 3. The mass of magnisium to be used:
Originally 0. 2g of magnisium Changed to 0. 1g because 0.2 was more than enough for the reaction to sustain a good set or results Evaluation of Preliminary trials: A number of mistakes were made here, mostly concerning the speed of the reaction and the over use of some of the chemicals in the experiment. I am more sure of the new measurements of chemicals and there reliability but think that it may be a good decision to measure out the amounts in moles to compare the results achieved with the official mole results, problem being this would prove difficult with such a large variation in concentration and I am not running the reaction to its full extent but over 40 seconds.
I am sure that the new variations of chemicals used after the preliminary tests will offer a more accurate set of readings than the prior set. Prediction: I predict that the higher the concentration of the sulphuric acid the more Hydrogen is released and so the faster the rate of reaction. Quantitative prediction: I predict that the following formula will apply to this experiment: Research: This section aims to provide a more detailed scientific theory, including analysis of the molecular scale concerning all aspects of this experiment.
The theory shown here will mainly be used as proof that the prediction above is accurate, but it can also be referred to throughout the rest of the this write up to explain anomalies or points of interest. Magnesium + Sulphuric acid ==> Magnesium sulphate + Hydrogen Mg (s) + H2SO4 (aq) ==> MgSO4 (aq) + H2 (g) As you can see from the formula above, Hydrogen is released as a result of sulphuric acid and magnesium reacts to make magnesium sulphate (Epsom salts). The speed (or ‘rate’) at which this hydrogen is released determines the rate of the entire reaction.
The fundamental question for this experiment is to discover whether increasing the surrounding concentration of the sulphuric acid speeds up the progression of the reaction. The way in which the four factors (shown in bold below) could affect the rate of reaction is described in basic here, along with an explanation of a molecular scale (shown in blue): 1. Temperature: The sulphuric acid can be heated to a specific temperature before the magnesium is added; thus altering the rate of the reaction. Different temperatures can be achieved using a Bunsen burner.
When a reaction has a higher temperature, the molecules within the reaction receive more energy. With more energy molecules move faster, and so the rate of the reaction between the molecules or two or more different substances increases. 2. Surface Area (of the magnesium): Using various forms of magnesium can change its surface area. There are four typical forms of magnesium: 1. Nuggets (spherical, approximately 1 cm in diameter) 2. Ribbon (approximately 3cm strips) 3. Turning (2mm shavings) 4. Powder The more surface area a substance like magnesium has the more molecules of that substance are open to the reaction at any one time.
With more reactant molecules available, the faster the rate of reaction. 3. Concentration (of the sulphuric acid) Sulphuric acid can be diluted to varying specification to create five different concentrations measured here in mol (m): If a substance has a high concentration level, then it will contain more molecules of the chemical, For example, if a liquid chemical is diluted with water, it will have a lower concentration level than the same chemical that is not diluted.
With more molecules of a certain chemical, there will be a higher opportunity of the two reactant molecules meeting, so increasing the rate of reaction. 4. A catalyst: There are four different types of catalyst that can be used in this experiment: 1. Manganese Dioxide (MnO2) 2. Potassium Dichromate (K2Cr2O7) 3. Potassium Permanganate (KMnO4) A catalyst is a substance added to a reaction to speed it up. For example, an enzyme is a catalyst, and can be added to certain biological reactions to increase the breakdown of certain food molecules. Prediction conclusion:
Having researched the way in which various factors (including concentration of sulphuric acid) can affect the rate of a reaction, I can safely say that a reaction with a higher concentration with a higher concentration of a reactant substance will have a faster rate than a reaction with a lower concentration. Results: Concentration Time (s) 1st run 2nd run 3rd run Mean 100% Graphs: Below are the graphs corresponding to the results table above. And as above they descend from highest to lowest concentration.
All anomalies are circled in red. Results observations: There are many anomalous results that can be seen from these results (circled in red), there also seems to be a very large difference in one run of results from the others in the 40% concentration results, where run-3 has a much higher hydrogen production rate than the other runs. There are many minor anomalies in all the graphs but other major ones can be seen in the end of run-2 in the 80% concentration results where the rate of reaction is a lot slower in the last 20 seconds of the experiment.
Also in the beginning of run-2 of the 100% concentration experiment the production is considerably higher. Other important anomalies can only be seen when a mean graph is put together. We can see that there are some anomalies over all half way into the 100% concentration reading and at the beginning of the 80% concentration experiment. But perhaps a more significant anomaly is the 20% concentration line, where when put into a mean average the reading goes down! I can still draw a line of best fit none the less but it shows that the practical needs to be refined.