Rates of Reactions Chem

A catalyst

increases rate of reaction without being used up at the end of reaction, does not affect products formed.

Enzyme is

a biological catalyst that increases the rate of reactions in living cells without being used up.

How can you measure the rate of reaction when a gas is given off?

Measure time and measure the volume of gas produced in an upside down measuring cylinder in a gas syringe. Measure time and the change in volume.

How can you measure the rate of reaction when a precipitate is formed?

Put a black cross below a beaker containing one reactant, Add the other reactant and time how long it takes for the cross to not be visible.

How would a fast rate of reaction be distinguished from a slow rate of reaction on a graph?

Steeper line and become horizontal sooner

Explain the effect of concentration on the rate of reaction, using the collision theory: Higher conc of reacting solutions

Higher conc of reacting solutions -> more reactant particles per unit volume -> higher collision frequency -> more opportunities for successful collisions per unit time

Explain the effect of pressure on the rate of reaction, using the collision theory: Increased pressure of reacting gases

Increased pressure of reacting gases -> more reactant particles per unit volume -> higher collision frequency -> more opportunities for successful collisions per unit time

Explain the effect of surface area on the rate of reaction, using the collision theory: Increased surface area of a solid

Increased surface area of a solid -> exposes more reactant particles at surface -> more frequent collisions between reactant particles -> more opportunities for successful collisions per unit time

Explain the effect of temperature on the rate of reaction, using the collision theory: Increasing the temperature

 Increasing the temperature -> more kinetic energy in the reactant particles -> More particles possess energy greater than the activation energy -> more opportunities for successful collisions per unit time

Explain the effect of a catalyst on the rate of reaction, using the collision theory

Adding a catalyst increases the rate of reaction as the activation energy needed for the reaction to occur is lowered, so more reactant particles have sufficient energy to collide with each other successfully