1. Unit 1 PPAs Do you know the main points?

2. PPA1 Effect of Concentration Changes On Reaction Rate 1.describe how the concentration of potassium iodide was varied during the reaction? 2.state two factors which had to be kept constant during the reaction? 3.state how was the reaction rate determined? 4.state the purpose in keeping the total volume of reaction mixture the same in each experiment? 5.state why the procedure adopted to determine the reaction time was effective and accurate? Can you …..

3. PPA2 Effect of Temperature On Reaction Rate 1.state two factors which had to be kept constant during the reaction? 2.state how was the reaction rate determined? 3.state why the beakers used in each experiment have to be dry? 4.state why might it be difficult to get an accurate reaction time if the experiment was carried out at room temperature? Can you …..

4. PPA3 Enthalpy of Combustion 1.draw a labelled diagram of the apparatus used to determine enthalpy of combustion? 2.list five measurements that are made during the experiment? 3.suggest 2 reasons why the theoretical value for enthalpy of combustion is always much higher than the experimental values? 4.say why the enthalpy of combustion always has a negative sign? Example 0.25 g of ethanol was burned and the energy released increased the temperature of water from 20oC to 32.5oC. Calculate the enthalpy of combustion of ethanol. Can you …..