Flashcards in Topic 7 - Rates Of Reaction Deck (25):
Equation for the rate of reaction?
Rate of reaction = amount used or product formed / time
Explain the precipitation experiment ?
Mix reactant solutions (which produce a precipitate ) and under the beaker place a piece of paper with a mark. After adding the substances together measure how long it takes for the mark to disappear - although test is subjective beacause of human error.
Describe the step of the change in mass experiment ?
We can measure rate of reaction using a mass balance. The quicker the reading on the balance drops the faster the reaction is. We know the reaction has finished when the balance stops changing.
Describe the volume of gas given off experiment...
This involves using a gas syringe to measure the volume given off. The more gas is given off during a set time interval the faster the reaction. We can tell it’s finished when no more gas is being produced.
How to work out the gradient of a curvy graph?
Change in y/change in x
Define a successful collision.
Collision with enough energy to react.
Describe an experiment to check how the surface area affects the rate of reaction.
Using a gas syringe take readings of gas produced by marble chips With HCl and CO2. Repeat the experiment with the same volume of acid , mass of chips but crunch them up more . Compare
Does the concentration of acid affects the rate and in what way ?
Higher concentration means higher rate. So yes
Describe how you could investigate how surface area of calcium carbonate affects the rate of reaction? Between calcium carbonate and hydrochloric acid..
Place a volume of acid with knows concentration in a conical flask. Add a known mass of calcium carbonate and join a gas syringe to the beaker. Take readings at regular time intervals. Repeat the experiment with the same volume,concentration and mass but increase surface area.
How can surface area be increased?
Cutting the object or elements in half.
How does the temperature effect rate of reaction. Why?
Higher temperature will mean faster rate of reaction. This is beacause particles move after so there is more frequent collisions and so successful collisions.
What does the rate of reaction depend on ?
Collision frequency and energy transferred during a collision.
Factors affecting rate of reaction ?
Concentration or pressure(only for gases)
How does the concentration or pressure increase rate of reaction ?
Higher concentration means there is more particles, therefore there is a higher chance for a collision
How does surface area increase rate of reaction?
More area means there is more space for particles to collide against. This means frequency of collisions will increase.
How does the temperature increase rate of reaction?
Particles move faster and so there is more collisions. Also this means there will be more energy per collisions since they’re moving faster .
Function of a catalyst?
Increases rate without being chemically changed or used up. They decrease the activation energy necessary.
Provide an example for a catalyst and explain it...
ENZYMES! They’re biological catalysts that speed up the reactions in living cells. Like respiration,photosynthesis or protein synthesis.
What is an exothermic reaction?
A reaction that gives out energy to the surroundings, usually as heat. This can be checked as temperature of surrounding should increase.
What is an endothermic reaction?
A reaction that take in energy from surroundings.
What labels need to be shown on a graph for exothermic reaction?
Activation energy, energy released ,products and reactants.
What labels need to be shown on a graph for endothermic reaction ?
Activation energy,energy absorbed,react and and products.
Equation for overall energy change ?
Energy to break bonds - energy to make bonds
What does a negative answer in the bond calculations mean?
Means an exothermic so a loss of energy.