rates of reaction

• The rate of reaction is how a given quantity or property changes.
• Rate of reaction = quantity of products (g) / time taken (s)
• Rate of reaction = quantity of reactions used (cm3) / time taken (s)
• Reactants go from high to low
• Products go from low to high
• The steeper the slope the faster the reaction.
• Collision is needed for a reaction to occur.
• The 3 factors that must occur for a reaction to take place are they must collide, the minimum amount of energy 

  and they must collide in the correct orientation.
• Not all collisions are successful. 
• The reactants must have energy so that they can break the bonds. The minimum amount of energy must decrease so that the bonds can be weakened. 
• Minimum amount of energy and activation energy are the same things.
• Activation energy is used to break the existing bonds in reactants to form new bonds. 
• Transition period is also called intermediate product & Activated complex 
• Rate of reaction measures how quickly reactants change into products.
• The 2 main methods to measure rate of reaction are measuring how quickly the reactants decrease and how quickly the products increase.
• An example of measuring reactants: to measure the reaction between marble chips and hydrochloric acid, the decrease in mass of reactants is measured.
• An example of measuring products: measuring the gain in volume of carbon dioxide using a gas syringe. Measure the volume of gas produced.
• Rate of reaction usually decreases as the reaction proceeds.
• The apparatus used to measure the loss of mass in a reaction is a balance scale. 
• The apparatus used to measure the gain in volume is a graduated gas syringe.
• The main factors that affect the rate of reaction are concentration, pressure, temperature, surface area and catalysts.
• Concentration is a measure of the amount or number of particles in a given volume.
• Concentration can be increased by increasing the number of particles while keeping the volume the same or increasing the frequency of collision.
• Pressure mainly increases the rate of reaction in gases.
• When pressure is increased the volume is decreased. If the volume decreases then the particles are closer which increases collision and leads to an increase in the rate of reaction.
• Increase in pressure = Decrease in volume = Particles become closer = frequent collision = increase in rate of reaction.
• Increase in temperature = increase in energy = particles become faster = frequent collision = increase in rate of reaction.
• The surface area has to do with particle size and the surface area is exposed.
• If the surface area is increased, particles are made into smaller pieces making more of the surface area exposed which allows frequent collision and increases the rate of reaction.
• Increase in surface area = particles are broken down into smaller pieces = more surface area exposed = frequent collision = increase in rate of reaction.
• A catalyst is something that speeds up a chemical reaction but at the end of the reaction has the same mass it had at the beginning of the reaction. It is not used up however it must take part in the reaction and remain unchanged.
• A catalyst works by providing an alternative pathway. For the reaction to occur this alternative pathway must have a lower activation energy.
• Catalysts are used in a manufacturer of ammonia. This catalyst is Fe - Haber process. As well as, contact process in the manufacturer of H2SO4 which is the catalyst in vanadium(v) oxide V2O5.
• The two types of catalysts are homogeneous and heterogeneous.
• In homogeneous catalysts, Is a solid catalyst is added to a gaseous mixture. The gas molecules adhere or stick to the surface of the solid catalyst and hence carry the reactants molecules closer to each other allowing them to react.
• Homogeneous catalysts provide an alternative pathway by lowering activation energy.