Chemical Changes And Structure #1: Rates Of Reaction Flashcards
Slow reactions
Large particles (lumps), low concentration (dilution), low temperature
Fast reactions
Small particles (powder), high concentration, high temperature
How do you determine what factor is affecting a chemical reaction?
You must only change one variable at a time
What is a variable?
Something that can be changed in a chemical reaction
What are some variables?
- temperature
- particle size
- concentration
- volume
- mass
How do you carry out a fair test?
By only changing one variable at a time
What must happen for a chemical reaction to occur?
The reactants particles must collide
How do collisions work?
The collision provides the energy to break the bonds in the reactant molecules and form the new bonds in the product
Not all collisions result in…
- A chemical reaction
- Those that do are said to be successful collisions
What makes a successful collision?
The particles must collide with:
- the correct geometry (the right angle)
- sufficient energy
Any factor which increases the number of collisions between reactant particles will also increase…
The rate of reaction
What is the effect of particle size on collision theory?
- As the particle size decreases, the surface area increases
- As the surface area increases, the area available for collisions to happen increases
- This increases the rate of reaction
What is the effect of concentration on collision theory?
- As the concentration of reactants increases, there is more particles and so more collisions
- Rate of reaction increases
What is the effect of temperature on collision theory?
As the temperature increases:
- the amount of energy a particle has increases
- the faster the particle moves around
- the more likely particles are to collide
the rate of reaction increases
All chemical reactions produce…
New substances