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• The temperature in the room may have altered.
A dependent variable is a variable you do not change during an experiment. Instead, it changes as a result of other changes you make.
The dependent variables in my experiment were:
• The rate of reaction.
• The volume of sodium thiosulphate.
The volume of sodium thiosulphate will remain unaffected throughout the whole experiment, Where as I will be changing the concentrations of hydrochloric acid. The volume of sodium thiosulphate will be 50cm³. The different concentrations of hydrochloric acid are 0.10M, 0.25M, 0.50M, 0.60M, 0.90M and 1.0M.
Now, I will discuss my prediction of what will happen during the experiment.
Prediction:
My prediction is,
• As I increase the concentration of hydrochloric acid and add it to the sodium thiosulphate the rate of reaction will decrease.
This happens because more particles are being added to the solution when the concentration increases. Therefore, this decreases the rate of reaction and the probability of a collision between reactant particles because there are more of them in the same volume and so increases the chance of a collision forming. This is where the collision theory starts in gases, increase in pressure means those molecules are closer together so there are more collisions. Theory: Rate is the extent of the change that takes place in a unit of time e.g. m/s. Reaction is the term that defines the reaction of when two or more particles collide to make a product. Chemical reactions only occur when reacting particles collide with each other with sufficient energy to react. The minimum amount of energy required to cause this reaction is called the activation energy. These reactions can proceed at different speeds for example: • Rusting is a slow reaction. • Burning is a fast reaction. There are four important factors which affect the rate of reaction and they are: • Concentration (pressure for gases) • Surface area • Catalyst • Temperature I will now begin with talking about how concentration affects the rate of reaction. Effect of Temperature: By increasing the temperature, particles gain more kinetic energy. Particles get more vigorous therefore collide more frequently this also increases the rate of reaction. This is also known as the thermal decomposition. . . …show more content…
Effect of Surface area:
If there is a greater surface area of a reactant there is a bigger chance of a collision occurring between the particles. If one of the reactants is a solid then breaking it up into smaller pieces will increase the surface area. This means the particles around it in the solution will have more to work to do so there will be more useful collisions.
Effect of Concentration:
Increasing the concentration means you are adding more particles to a solution which also increases the reaction time.
If the concentration of any reactant in a solution is increased, the rate of reaction is increased.
If the solution is made more concentrated is made more concentrated it means there are more particles of reactant knocking about between the water molecules which makes collisions between the important particles more likely. In a gas, increasing the pressure means the molecules are more squashed up together so there are going to be more collisions.
Effect of a Catalyst: A catalyst is a substance which increases the rate of reaction, without being used up in the process. Catalysts are specific i.e. different reactions need different catalysts. Since catalysts are not used up, only small amounts of catalysts are needed. Catalysts work by reducing the activation energy – the minimum energy needed for a reaction to happen. Catalysts increase the rate of a reaction by helping to break the chemical bonds in reactant molecules and provide a 'different pathway' for the reaction. This means the activation energy is also reduced. A catalyst also increases the number of collisions in a given time. A solid catalyst works by giving the reacting particles a surface to stick to where they can bump into each other. This increases the number of successful collisions. I will now give a list of the equipment used in the experiment, state the job and key pieces for it and I will examine the level of accuracy in which it measures in an actual experiment. Activation energy: The activation energy or the energy that must be overcome in order for a chemical reaction to occur. Activation energy may otherwise be denoted as the minimum energy necessary for a specific chemical reaction to
A dependent variable is a variable you do not change during an experiment. Instead, it changes as a result of other changes you make.
The dependent variables in my experiment were:
• The rate of reaction.
• The volume of sodium thiosulphate.
The volume of sodium thiosulphate will remain unaffected throughout the whole experiment, Where as I will be changing the concentrations of hydrochloric acid. The volume of sodium thiosulphate will be 50cm³. The different concentrations of hydrochloric acid are 0.10M, 0.25M, 0.50M, 0.60M, 0.90M and 1.0M.
Now, I will discuss my prediction of what will happen during the experiment.
Prediction:
My prediction is,
• As I increase the concentration of hydrochloric acid and add it to the sodium thiosulphate the rate of reaction will decrease.
This happens because more particles are being added to the solution when the concentration increases. Therefore, this decreases the rate of reaction and the probability of a collision between reactant particles because there are more of them in the same volume and so increases the chance of a collision forming. This is where the collision theory starts in gases, increase in pressure means those molecules are closer together so there are more collisions. Theory: Rate is the extent of the change that takes place in a unit of time e.g. m/s. Reaction is the term that defines the reaction of when two or more particles collide to make a product. Chemical reactions only occur when reacting particles collide with each other with sufficient energy to react. The minimum amount of energy required to cause this reaction is called the activation energy. These reactions can proceed at different speeds for example: • Rusting is a slow reaction. • Burning is a fast reaction. There are four important factors which affect the rate of reaction and they are: • Concentration (pressure for gases) • Surface area • Catalyst • Temperature I will now begin with talking about how concentration affects the rate of reaction. Effect of Temperature: By increasing the temperature, particles gain more kinetic energy. Particles get more vigorous therefore collide more frequently this also increases the rate of reaction. This is also known as the thermal decomposition. . . …show more content…
Effect of Surface area:
If there is a greater surface area of a reactant there is a bigger chance of a collision occurring between the particles. If one of the reactants is a solid then breaking it up into smaller pieces will increase the surface area. This means the particles around it in the solution will have more to work to do so there will be more useful collisions.
Effect of Concentration:
Increasing the concentration means you are adding more particles to a solution which also increases the reaction time.
If the concentration of any reactant in a solution is increased, the rate of reaction is increased.
If the solution is made more concentrated is made more concentrated it means there are more particles of reactant knocking about between the water molecules which makes collisions between the important particles more likely. In a gas, increasing the pressure means the molecules are more squashed up together so there are going to be more collisions.
Effect of a Catalyst: A catalyst is a substance which increases the rate of reaction, without being used up in the process. Catalysts are specific i.e. different reactions need different catalysts. Since catalysts are not used up, only small amounts of catalysts are needed. Catalysts work by reducing the activation energy – the minimum energy needed for a reaction to happen. Catalysts increase the rate of a reaction by helping to break the chemical bonds in reactant molecules and provide a 'different pathway' for the reaction. This means the activation energy is also reduced. A catalyst also increases the number of collisions in a given time. A solid catalyst works by giving the reacting particles a surface to stick to where they can bump into each other. This increases the number of successful collisions. I will now give a list of the equipment used in the experiment, state the job and key pieces for it and I will examine the level of accuracy in which it measures in an actual experiment. Activation energy: The activation energy or the energy that must be overcome in order for a chemical reaction to occur. Activation energy may otherwise be denoted as the minimum energy necessary for a specific chemical reaction to