Topic 5 - rates and equillibrium Flashcards
Describe practical methods for investigating the rate of a reaction
change in mass of a reactant or a product and the formation of a gas
What does a catalyst do?
increases the rate of a reaction and is unchanged at the end of a reaction and decreases the activation energy, Ea, of a reaction
What is collision theory
- Particles must collide for a reaction to occur.
- Particles require a minimum energy, the activation energy, in order to break their bonds and react.
- If particles have suficient energy, the collision will be successful.
- Not all collisions are successful.
- In order to increase the rate of a reaction we must increase the chance of a successful collision.
What effects the rate of reaction?
Increasing the surface area of a solid increases the rate of a reaction.
Increasing the concentration of a solution increases the rate of a reaction.
Increasing the pressure of a gas increases the rate of a reaction.
Increasing the temperature increases the rate of a reaction.
Using a catalyst increases the rate of a reaction.
Calculate volumes of solutions and concentrations of solutions expressed in g /dm³ and mol/dm³, including conversion between cm³ and dm³
cm³ ——÷——> dm³
dm³——x——->cm³
e.g) 25cm³ / 1000 = 0.025dm³
What symbol shows a reversible reaction.
⇌
Describe how changing the conditions can change the direction of a reversible reaction for:
(a) the effect of heat on hydrated compounds
(b) the addition of water to anhydrous compounds limited to copper(II) sulfate and cobalt(II) chloride
By adding heat to a hydrated compound it dehydrates the compound.
By adding water to an anhydrous compound it is hydrated.
How do you know if a reaction is at equillibrium?
- The reversible reaction must be in a closed system.
- The forward and backward reactions occur at the same rates.
- The concentration of reactants and products stays the same.
Haber process equation.
N2(g) + 3H2(g) ⇌ 2NH3(g)
What sources are used in the haber process?
hydrogen and nitrogen.
Typical conditions for the haber process
450 degrees celsius
200 atm (atomspheres)
State the symbol equation for the conversion of sulfur dioxide to sulfur trioxide in the Contact process
2SO2(g) + O2(g) ⇌ 2SO3(g)
sources for contact process
sulfur dioxide (burning sulfur or roasting sulfide ores) and oxygen (air).
typical conditions for contact process
450 degrees celsius
2 atm (atmospheres)
Why are these conditions used in the haber process and the conditions for the contact process?
Because in the haber process for example, these conditions will give us the highest yield of ammonia.
