Rate of reaction Flashcards
what are the labels given to the chemicals in a word equation
- The substances that are involved in a chemical reaction and that are changed by it are called reactants
-The substances that are produced by a chemical reactions are called products
What are the four indicators that show there is a chemical reaction that is happening
- Effervescence (A liquid giving of bubbles/fizzing)
- Colour change
- Percipitation (the process of percipitating a substance from a soloution)
-Energy (temperature change)
When can a colour change happen?
- A colour change can happen when a compound is broken down by heating it. This is also called thermal decomposition
What does every chemical reaction involve?
- Every chemical reaction involves a change in energy because different substances hold different amounts of energy
- During the reaction bonds inside the substances must be broken and new chemical bonds must be made in the products that are being made
What happens in an exothermic reaction?
In an exothermic reaction the reactants hold more energy than the products, so exothermic reactions release energy.
Whats another way that energy could be released in a chemical reaction?
Energy could also be released in a chemical reaction in the form of a sound or light being produced but the most exciting chemical reactions will probably have all three going on
What happens in an endothermic reaction?
In an endothermic reaction, the reactants have less energy than the products, so more energy is needed for the reaction to take place (ice packs)
What are the four factors that affect the rate (speed up) a chemical reaction?
- Catalyst
- Particle size
- Concentration
- Temperature
What happens if a temperature is used to speed up a reaction?
At low temperature the particles move slowly and seldom collide. At high temperature the particles move quickly and collide more often.If the temperature is increased, the particles have more energy and so move quicker. Increasing the temperature increases the rate of reaction because the particles collide more often and with more energy. The higher the temperature, the faster the rate of a reaction will be.
What is an example of a temperature reaction?
Sodium and chlorine react vigorously when heated, giving an orange flame and producing white sodium chloride
What happens during a concentration reaction?
If the concentration of reactants is increased, there are more reactant particles moving together. There will be more collisions and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.
What happens during a particle size concentration
By decreasing the particle size of a reactant, we are increasing its surface area. The greater the surface area, the higher the chance of collisions, thus the faster the rate of reaction. The smaller the particle size the faster the reaction
What happens during a catalyst reaction?
A catalyst increases the rate of a reaction but it is not used up in the reaction. If a catalyst is present, the reacting particles can collide more successfully with less energy and so the reaction can take place at a lower temperature
What is an example of a catalyst?
Enzymes are biological catalysts.
They occur naturally in the body and help with digestion.
They are used in the production of alcohol (zymase) and digestion of food (amylase). Enzymes are specific. This means that they can only catalyse one reaction.
What is the definition of rate of reaction?
The rate of a chemical reaction is a measure of how fast the reactants are being used up and how fast the products are being made
