Chemistry Carousel 2

• The rate of reaction will increase when the temperature increases.
• To measure the rate of reaction from a graph, one needs to draw a tangent to the curve and calculate the gradient.
• A reversible reaction is a reaction which can go from reactants to products but also from products to reactants.
• Measuring the quantity of a reactant or product would be in grams or cm3
• The law of conservation of energy states that energy cannot be created or destroyed yet can be transferred from one store to another.
• Increasing the pressure of a gas, increases the rate of reaction.
• Increasing the surface area, increases the rate of reaction.
• The reactants of the surroundings during an endothermic reaction, decreases.
• Increasing the concentration, increases the rate of reaction due to more concentration, means more particles in solution, therefore more frequent collisions between reactants.
• Increasing the temperature, increases the rate of reaction due to it increasing the speed at which particles move therefore more frequent collisions. The increase of number of particles which have the activation energy therefore more collisions result in reaction.
• The formula for mean rate of reaction (in terms of products) is quantity of reactant product formed / time taken.
• Self-heating cans and hand warmers are examples of exothermic reactions.
• The collision theory is the theory that chemical reactions only occur when particles collide with sufficient energy.
• Five factors which affect the rate of reaction is temperature, surface area of a solid, concentration of reactants, pressure of gases, catalyst.
• An endothermic reaction is a reaction where energy is transferred from the surroundings.
• Increasing the pressure of a gas increases the rate of reaction due to less space for the particles to move around in, resulting in more frequent collisions.
• A reaction profile is a diagram which shows whether the reactants have more or less energy than the products.
• Breaking of bonds is endothermic and making of bonds is exothermic.
• An exothermic reaction is reaction where energy is transferred to the surroundings.
• A catalyst is something which changes the rate of a reaction but is not used up in that reaction.
• Thermal decomposition reactions, citric acid and sodium hydrogen carbonate are two examples of endothermic reactions.
• Increasing the surface area, increases the rate of reaction due to more particles are being able to collide, therefore there are more frequent collisions between reactants.
• Combustion and respiration are examples of an exothermic reaction.
• To work out the overall energy change of a reaction, one is to work out the difference between the energy required to break all the bonds in the reactants and the energy released to form all the bonds in the products.
• The activation energy, is the energy a particle requires in order to collide with another.