# The Effect of Changing the Concentration of Hydrochloric Acid on the Rate of Its Reaction With Marble Chips

A reaction is when two particles (reactants) join to form a new product or products . A rate is a measure of how fast or how slow something is. Rate is a measurement of the change that happens in a single unit of time. The rate of a chemical reaction is how fast the reactants react. To find a rate of reaction you measure the amount of product given off by the reaction in a unit of time . In this piece of coursework I will be investigating whether the concentration of hydrochloric acid alters the rate of reaction with marble chips . In this experiment hydrochloric acid is added to marble chips (calcium carbonate) . The two reactants collide with each other the hydrochloric acid acts as a catalyst for the two reactants which causes particles from the reactants to collide into one another the higher the concentration of acid molecules the faster the gas will be given off. The rate of reaction is increased by three factors . Ÿ Higher temperatures Temperature alters the rate of a reaction by supplying the reactant particles with more energy, the more energy the reactants have the faster they move around increasing they?re are chance of bumping into one another and having a successful collision Ÿ The greater the surface area of the reactants the more particles are available for a successful collision. Ÿ Concentration effects the rate of a reaction because the higher the concentration of particles the greater the chance of a successful collision. The equation for this experiment is: HCL+CACO3=CO2 (hydrochloric acid + calcium carbonate = carbon dioxide) To do this experiment I am going to get 10 grams of marble chip and weigh them on scales I will then add the hydrochloric acid I add 50 ml of acid each time I am going to use 5 different molars of acid ranging from 1to 5 when the acid is added to the marble chip I place cotton wool inside the conical flask and the two reactants are reacting I measure the amount of weight lost from the conical flask , this weight loss was due to the gas from the reaction being released ( carbon dioxide). My group and I recorded the weight lost every 20 seconds for 140 seconds to measure the rate of reaction between the CACO3 and hcl. We then record the amount of weight lost from the conical flask every 20 seconds this was used to determine the rate of reaction between the two chemicals . every time we conducted the experiment we used a different molar of acid to see if it affected the rate of reaction. To make this experiment a fair test we conducted every experiment twice to see that there were no bad results. To conduct this method for our experiment we did preliminary experiments to determine which type of method best suited the experiment and how we could get the most accurate results for our experiment. We tried to different types of experiments one of which we used a water bath to see the gas exchange and how fast that happened to determine the rate of reaction and also our method in which we weighed our conical flask because we deemed this to have the most accurate results . Apparatus
weighing scales ? to weigh marble chips and to weigh the conical