Does Concentrated Acid or Diluted Acid React Faster? :: Science Experiments Reaction Rates Essays

Does Concentrated Acid or Diluted Acid React Faster? Plan I am going to carry out a reaction between Magnesium ribbon and Hydrochloric acid. The aim of this investigation is to work out which reacts faster, concentrated acid or diluted acid. I will judge if the reaction is fast or slow by observing the bubbles which occur during the reaction and also observe if the Magnesium has disappeared. Only the concentration of the acid will be changed - the Magnesium is a solid. Magnesium + Hydrochloric Acid Magnesium Chloride + Hydrogen Mg(s) + 2HCl(aq) MgCl(aq) + H2 (g) There are four main factors which may affect rate of reaction. These are: - 1. Concentration 2. Temperature 3. Catalyst 4. Surface area CONCENTRATION- if the concentration of the acid is increased, the rate goes faster. In a concentrated acid there are more particles in it this means that there is a more chance of successful collisions occurring. If the acid was diluted, there are not many acid particles, which means that there is not much chance of an acid particle hitting a magnesium atom. At the start, there are plenty of Magnesium atoms and acid particles but they get used up during successful collisions. After, a time there a fewer Magnesium atoms and the acid is less concentrated so the reaction slows down. This graph shows this: - volume of hydrogen Time Diluted Acid Concentrated Acid = Acid particle = water molecule = Magnesiumatom TEMPERATURE - at low temperatures the particles of reacting substances don't have enough energy. So if the substances were heated this would mean the particles take in energy. This causes them to move faster and collide vigorously very often. Also making more successful collisions. Therefore the rate of reaction increases. CATALYST - using a catalyst can speed up reactions. If there is a catalyst in the reaction then the collision needs less energy in order to be successful. This results into more collisions becoming successful, so the reaction goes faster, catalysts are very important in industry. Reactions are speeded up at low temperatures, which means less fuel is needed so money is saved. SURFACE AREA - if the Magnesium had a large surface area the atoms in the outer layer will only collide with the acid particles but if the metal was powdered, many more atoms are exposed, so there is a greater chance of successful collisions. Concentrated Acid = Acid particle = water molecule = Magnesium atom COLLISION THEORY The Collision Theory is used to predict the rate of reaction. The Theory is based on the fact that for a reaction to take place, it is