Factors That Affect the Rate of Reaction
Background
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We can measure the rate of reaction by measuring the rate of change by
either,
- one of the reactants disappearing with time
- one of the product forming with time.
A chemical reaction can only occur between particles when they collide
(hit each other). Particles may be atoms, ions or molecules.
There is a minimum amount of energy which colliding particles need in
order to react with each other. If the colliding particles have less
then this minimum energy, then they just bounce off each other and no
reaction occurs. This minimum is called the minimum energy.
Collision Theory:
- particles must collide
- with sufficient energy to break existing bonds
- with the correct orientation
Measuring rates:
We can measure how quickly products form or we can also measure how
quickly reactants are used up.
Here are some graphs which you can get whilst studying these two
different methods,
Factors that affect the rate of reaction:
1.Raising the temperature has the same effect on all three reactions.
Raising the temperature makes the particles move faster. This means
that more particles collide with each other per second.
The rate of the reaction increases. Also, the faster the particles are
travelling, the greater is the proportion of them which will have the
required minimum energy for reaction to occur. As a general guide,
raising the temperature of a reaction by 10 °C
will double the rate of the reaction.
The gradient of the plot will be twice as steep.
Here is a prediction graph for an experiment investigating the effect
of temperature on the rate of a reaction:
2.Increasing the concentration (in solution).
Increasing the concentration of a substance in solution
means that there will be more particles per dm3 of that
substance.Themore particles that there are, the more will collide per
second,
and so the rate of the reaction increases.
In a substance the rate of reaction will be quicker if it has a large
It is important however to note that the NH4 and K ions are still in
the large beaker pour in some more hot water or if it is too hot pour
In this experiment there five different phases and in each a different factor of the Collision Theory was tested. The first phase was called, Nature of the Reactants and it had three parts to it. In the first part of it which was steps 1-4, 5 pieces of mossy zinc were put into 3ml of 2M H_2 〖SO〗_4 and during this time bubbles were produced. After a few minutes the zinc was removed from the acid and it was now clean zinc.
Some factors that could cause the rate of reaction to vary are simple things like temperature. The temperature could affect things like the rate of successful collisions.
The Effect of Concentration on Reaction Rate Introduction I will be carrying out an investigation into how concentration affects reaction rate. I will be looking at sodium thiosulphate and hydrochloric acid. The reaction is represented by the following equation: [IMAGE]Na2S2O3(aq) + 2HCl(aq) 2NaCl(aq) + H2O(l) + SO2 (g) + S (s) I will add the hydrochloric acid to the Sodium Thiosulphate and time how log it takes for the mixture to turn opaque. I will use a different concentration of Sodium Thiosulphate each time. Prediction
have decided what size chips I I'm going to use I will keep the same
The Effect of Temperature on the Rate of a Reaction Aim and Hypothesis The investigation that we have chosen to do is how the effect of temperature affects the rate of reaction of hydrogen peroxide to water and oxygen using the enzyme catalase. I predict that the higher the temperature the faster the rate of reaction will be and the more oxygen there will be given off. I've based this prediction on kinetic theory (every 10 degree rise in temperature the rate of reaction doubles.) This is because the substrate will lock on twice as fast, as it is travelling twice as fast.
· We then got a square piece of paper and then placed it on the
Kinetics is the discovery and study of the reaction rates of chemical reactions. These reaction rates involve the pace or rate at which a reaction progresses. Many specific conditions can affect the reaction rate value; furthermore, the factors include the concentration of the reactants, the polarity of the solvent, and temperature1. The rate of reaction can be determined and studied using a rate law, an equation that correlates the rate with concentrations and a rate constant. This experiment’s reaction involving t-butyl chloride has a first order reaction rate, which means that the reaction’s rate law equation is the first order equation shown below.
The effect of these factors can be explained using collision theory. Reactions occur when the reactant particles collide, provided the colliding particles have enough energy for the reaction to take place. As the molecules approach their electron clouds repel. This requires energy – the minimum amount of which is called the ‘activation enthalpy’ - and comes from translational, vibrational, and rotational energy of each molecule. If there is enough energy available, this repulsion is overcome and the molecules get close enough for attractions between the molecules to cause a rearrangement of bonds and therefore an ‘effective’ reaction has taken place. The more collisions of particles with kinetic energy over the activation enthalpy that occur, the faster the overall reaction. During this investigation I am focusing on the effect of temperature and concentration while aiming to maintain other rate determining factors at a constant level in order to ensure reliable results.
The purpose of this investigation is to investigate how one variable (temperature in this experiment) will affect the rate of a chemical reaction. The rate of any chemical reaction always depends on the reactant concentrations, surface area of reactants and the temperature.
that the rate of reaction must be fast enough to make as much of the
Chemical kinetics is the study and examination of chemical reactions regarding re-arrangement of atoms, reaction rates, effect of various variables, and more. Chemical reaction rates, are the rates of change in amounts or concentrations of either products or reactants. Concentration of solutions, surface area, catalysts, temperature and the nature of reactants are all factors that can influence a rate of reaction. Increasing the concentration of a solution allows the rate of reaction to increase because highly concentrated solutions have more molecules and as a result the molecules collide faster. Surface area also affects a
The rate of reaction is how quickly or slowly reactants in chemical reactants turn into products. A low reaction rate is when the reaction takes a long time to take place; hence, a reaction that occurs quickly has a high reaction rate. A rate refers to how slow or quick the product is produced. It is possible to control the rate of chemical reactions and speed up or slow down the rate of chemical reactions by altering three main factors which are temperature, concentration and the surface area. When the temperature of the reactants increases, the molecules vibrate at a more intense speed therefore colliding with each other more frequently and with increased energy resulting in a greater rate of reaction. Accordingly, as the temperature decreases the molecules will move slower, colliding less frequently and with decreased energy resulting in the rate of reaction decreasing. Concentration is how much solute is dissolved into a solution and is also a factor that affects the rate of reaction. When the concentration is greater this means there is an increased amount of reactant atoms and molecules resulting in a higher chance that collisions between molecules will occur. A higher collision rate means a higher reaction rate. Consequently at lower concentrations there are reduced chances of the molecules colliding resulting in a lower reaction rate. The measurement of how much an area of a solid is exposed is called the surface area. The quicker a reaction will occur the more finely divided the solid is. For example, a powdered solid will usually have a greater rate of reaction in comparison to a solid lump that contains the same mass for it has a lower surface area than the powdered solid.