The reason I chose to do this investigation was because I have previously done it so I know what kind of results to expect. In the preliminary experiment we used hydrochloric acid that had a concentration of two molar 2. Marble Chip Investigation Method 1. I will keep the volume of the hydrochloric acid the same. Place the flask on scales.
Additionally for the preliminary experiment I timed the reaction until 50 cm3 of carbon dioxide gad was produced, because I found this to be a fairly quick method but yet accurate, although not as accurate as the methods I used for the main experiment. A more concentrated substance has more reactant particles in a given volume than a more dilute substance. In one hole a long glass jet tube is inserted and in the other a dropper with few drops of water. Scientific knowledge: Marble chips erode when they are exposed to acid rain or pollution. Catalysts are usually transition metals.
Bearing in mind, that the results for that particular concentration were consistent but this has not been reflected on the best fit curves. Method: Firstly, I will measure out 0. Also at this time people remove their goggles to pack up. Additionally the amount of carbon dioxide given out can me measured accurately and fairly quickly. I think this because of the particle theory. Also the experiment I shall I do was done in Chemistry For You by Laurie Ryan and so using the evidence I collected from these experiments I know what type of results to anticipate.
The experiment will be repeated and carried out in the same way; only the concentration will be changed. I was expecting some anomalies which could occur from human error of recording results, dirty equipment, the wrong strength acid, there is a wide range of possibilities that could have gone wrong. There are many other techniques but remember, practice makes perfect. I could develop my investigation in a few ways such as: o See how temperature affects rate of reaction. The calcium displaces the hydrogen from the hydrochloric acid which results in calcium chloride marble in being formed I chose concentration as the variable because of its ease in changing in comparison to the other variables — temperature, surface area, concentration and catalyst. · A Stand - To hold up the measuring cylinder. Concentration Pressure for gases 3.
Catalysts are important in industry because they reduce costs. So, this means that the higher the concentration of my acid the faster the reaction. This would create a safety hazard, maybe causing slipping. Then we weighed out the marble chips. Evaluation: My results worked out just as I had hoped with out any results that were anomalies. Carbonates react with strong acids to give off carbon dioxide and water.
If more surface area is available, the number of particles of the solid reactant available will increase. Preliminary Experiment Before we undertook our full experiment we needed to carry out a preliminary experiment. A common technique is to hold the marble with your forefinger in a 'U' shape and your thumb under or behind the marble. We used treated agar blocks to model artificial cells because their surface area and volume could be easily measured, and they visually show the amount of diffusion. This meant that the water was still in the cylinder After this we measured out 20ml of one of the acid concentrations 0. The more particles present, the bigger the chance of a collision making the reaction faster.
. Because this would take less time I could also have done more repeats to get a more reliable set of results. I could develop my investigation in a few ways such as: o See how temperature affects rate of reaction. I will use concentrations of 50cm3 using different volumes of water and acid. I have a good range of results and think that I could see what the pattern would be beyond this range.
The solution fizzes and gives off the gas carbon dioxide. Introduction We are going to do an experiment to see how surface area effects the rate of reaction when added to hydrochloric acid. I will then record how long it takes for it to fill the measuring cylinder up. I will look at the various factors affecting the reaction and select one variable to change, while the others keep constant in order to carry out a deta. The rate of reaction increases when the surface area of a solid reactant is increased. The concentration of acid remained the same throughout the preliminary experiment because it was the values for the constants that we are finding out. This is all due to the collision theory.
I shall use the following readings: o 10cm of acid and 40cm of water. Obtaining Evidence: To record my results as accurately as possible I designed the below table. I chose not to keep the concentration constant because it is easy to change and in comparison to these three other variables I think that it will be the quickest and most accurate variable. Experiment one: Experiment two: Time secs 0. To change the concentration of a solution, we dilute it by adding water. I diluted the acid by adding 20ml of water to 20ml of acid.