6rate&extent of chemical change

Cards (33)

  • what is the rate of reaction
    a measure of how quickly a reactant is used up or a product is formed
  • what is the equation for rate of reaction
    quantity used or product made / time taken
  • what is the equation for mean rate of reaction
    mean volume collected / time
  • what does a steeper line on a rate of reaction graph mean
    faster the rate of reaction
  • what does a quick reaction mean the line will look like on a rate of reaction graph
    becomes flat in the least amount of time
  • as volume increases what happens to the rate of reaction
    decreases
  • what is activation energy
    minimum amount of energy needed for a reaction to occur
  • what does the rate of chemical reactions depend on (collision theory)
    -collision frequency of reacting particles
    -energy transferred during collisions
  • what are the factors that affect the rate of reaction
    -concentration/pressure
    -temperature
    -surface area
    -add of a catalyst
  • what happens when temperature increases in the reaction
    -particles have energy greater than or equal to the activation energy /more kinetic energy so move faster
    -more frequent collision
    -increases rate of reaction
  • what happens when the concentration increases in the reaction
    -more particles in a given volume
    -more frequent collisions
    -increases rate of reaction
  • what happens when surface area is increased in the reaction
    -more particles available to react at a given time
    -more frequent collision
    -increases rate of reaction
  • what is a catalyst
    substance that speeds up a reaction without being used up itself, not part of overall reaction equation
  • how do catalysts works
    by decreasing the activation energy needed for reaction to occur by providing an alternative pathway with lower activation energy
  • what do enzymes act as
    biological catalyst, catalyse reactions in living things
  • how do you find the rate of reaction from a graph
    find the tangent
  • what is a reversible reaction
    when a reaction can reverse so that the products can change back to the reactants again
  • if a reversible reaction is endothermic in one direction what is it in the other direction
    exothermic
  • what is the symbol for a reversible reaction 

    .
  • what happens to make a reaction reach its equilibrium
    as the reactants concentration falls, the forward reaction will slow down but as more product is made and concentration rises the backward reaction will speed up, they will eventually happen at the same rate, reaching equilibrium
  • what is equilibrium
    when the forward and reverse reaction are occurring at the same rate in a closed system, no overall effect, concentrations won’t change
  • what is a closed system
    where neither of the products or reactants can enter or leave
  • what does it mean if the equilibrium lies to the right
    the concentration of the products is greater than that of the reactants
  • what does it mean if the equilibrium lies to the left
    the concentration of reactants is greater than that of the product
  • what is le chateliers principle
    the idea that if you change the conditions of a reversible reaction at equilibrium, the system will shift to counteract that change
  • what can le chateliers principle be used to predict
    the effect of any changed you make to a reaction system
  • what happens when concentration of the reactants is increased in an equilibrium reaction
    the position of the equilibrium will shift right to favour the products until the equilibrium is re-established
  • what happens when the concentration of the reactants is decreased in an equilibrium reaction
    the position of the equilibrium will stay on the left to favour the reactants until the equilibrium is re-established
  • in what 2 cases can pressure effect the equilibrium
    -if the molecules are gases
    -if there are a different number of molecules (moles) on each side of the equation
  • what happens if the pressure is increased in the an equilibrium reaction
    the position of the equilibrium shifts to the side with the fewest molecules of gas until the equilibrium is re-established
  • what happens if the pressure is decreased in an equilibrium reaction
    the position of the equilibrium shofts to the side with the most molecules of gas until the equilibrium is re-established
  • what happens if the temperature of an equilibrium reaction is increased
    the position of equilibrium will shift in the endothermic direction to lower the temperature by absorbing energy until the equilibrium is re-established, more products for the endothermic reactions
  • what happens if the temperature of an equilibrium reaction is decreased
    the position of the equilibrium will shift in the exothermic direction to increase the temperature by releasing energy until the equilibrium is re-established, more products for the exothermic reactions