Hydrochloric acid and Marble Chips

the marble chips are powdered then the reaction will happen faster because more of the chip will be exposed to the acid and they will react quicklyPredictionI predict that if the concentration of the HCl is doubled then the experiment will happen twice as fast. This is because twice as many HCl particles will be present than previously and there will be twice as much chance of the calcium carbonate chips colliding with the concentrated hydrochloric acid. Therefore when the concentration is double the time take for the reaction should be halved.When the surface area of the calcium carbonate chips is doubled there will be twice as much chance of it colliding with the Hydrochloric acid. Therefore I predict that when the surface area is doubled, the time taken for the experiment is halved.A temperature increase of 10 C will see the time taken for the experiment halved because energy of collisions in the particles increases, this means that there are going to be more successful collisions.IntroductionCollision theory - Collisions between reactant particles are needed for the reaction to take place in order to form a product. Some collisions are successful and give a product while others don't because particles don't have enough energy.Activation energy - The amount of energy needed for the reaction to be started. If there is enough energy then the reaction takes place and a product is formed, but if there isn't enough then no reaction takes place. There are two possibilities for increasing the rate of reaction:1. The activation energy is reduced so that there is a better chance of particles having enough energy to react. Reactants will need less energy to react.2. The number and strength of collisions is increased so that the reaction can happen faster. If the particles have more energy then more particles will be able to react.Solid reactants like marble chips are effected by surface area, the larger the surface area the more collisions that will take place. This will increase the rate of reaction and decrease the time taken.Liquid/ Aqueous reactants rely on collisions for more collisions to take place. In a concentrated acid solution there are more acid particles so more collisions will take place. There will be an increase in the product formed in a certain time.When the temperature is increased, the particles will have more energy, so they will move faster. This will result in the particles colliding more frequently and increasing the speed of the reaction. Also when they have more energy there will be more chance of the collisions being successful because the activation energy will be attainable.The addition of a catalyst will reduce the activation energy and makes more successful collisions. The reaction will be faster but the catalyst will not be used up during the reaction. When the activation rate is lower not much energy is needed to make the reaction successful. Planning for the experimentVariables Independent - Concentration of the Hydrochloric acid solutionDependent - The amount of CO producedControl - Temperature Surface areaAmount of HCl Mass of marble chipsApparatusThe solutions with different concentrations of acid have to be prepared before the reactions can start. The solution has to have a total volume of 10cm . The following solutions should be prepared by mixing water and the acid in a set ratio. When the solutions have been prepared the apparatus has to be set up. The following equipment will be needed for the experiment.Hydrochloric acidWaterCalcium Carbonate chipsConical flaskGlass capillarySyringeRubber bungSpatulaClampStandMeasuring cylinderStopwatchTop pan balanceMethodWhen the apparatus has been set up as shown above, 10 cm of the acid solution will be measured using a measuring cylinder. This will be poured into a conical flask. 3g of powdered CaCO chips will be weighed out using a top pan balance. This will be put into the conical flask and the rubber bung attached to the syringe will be put over it immediately afterwards. At the same time the stopwatch will be started. After every ten seconds the amount of CO released will be recorded by looking at the measurement on the syringe. This will be done for 100 seconds so by the end of the experiment 10 readings should be obtained.The experiment will be repeated and carried out in the same way, only the concentration will be changed. A less or mare concentrated solution will be used but the total volume of the solution will stay the same. EvaluationThe results show that the more concentrated the acid is then the faster the reaction happens. When there was 10 parts acid and no water, the reaction takes place much faster compared to when there was only 1 part acid and 9 parts water. I the reaction with concentrated acid 65 cm of carbon dioxide is produced in the first 10 seconds while only 3 cm of carbon dioxide is produced by using the least concentrated solution.There is no pattern as to how much of an increase there is because when the concentration is doubled from 5:5 to 10:0. The amount of carbon dioxide produced in the first 10 seconds doesn't double but goes from 17 to 65 which is more than triple.These results are not very accurate and can be improved. If the experiment is done twice and the average is taking the results will be more accurate.ConclusionOverall the results obtained were quite accurate and showed that an increase in the concentration of the acid means that the rate of the reaction increases and the time taken is decreased.