energetics and rates of reaction and reversible reactions

how is hydrating and dehydrating copper sulfate reversible

as when it's heated it thermally decomposes to anhydrous cooper sulfate but when water is added back it turns blue and is hydrated again.

how can the energy change be calculated from bond energies.

total energy of bonds broken - total energy of bonds made.

when can a reversible reaction reach dynamic equilibrium

when it takes place in a sealed container

Explain in terms of particles, why an increase in temperature increases the rate of a chemical reaction. (3 marks)

· As the temperature increases, the reacting particles will gain more kinetic energy. · The particle will move faster. · This will result into more successful collisions per second

The rate of a chemical reaction increases as the concentration of the reactant particles increases. Explain this relationship, in terms of particles.

· Increase in concentration will result in to an increase in the number of reactant particles, in the same volume. · The reactant particles will be close to each other. · There will be more successful collisions per second.

how does changing pressure affect the position of equilibrium.

- if it's increased then it will encourage the reaction that produces fewer molecules of gas so equilibrium will shift to that side - if it's decreased then it will encourage the reaction which produces more moles of gas so equilibrium will shift to that side.

how does changing the temp affect the position of equilibrium

- if temp is increased the endothermic reaction will be favored so equilibrium will shift in the direction of that reaction - if temp is decreased then the exothermic reaction will be favored and equilibrium will shift in the direction of that reaction.

what are 3 characteristics of a reaction at dynamic equilibrium

- the forward and backward reactions occur at the same rate. - the concentrations of the reactants and the products remain the same. - a catalyst speeds up the reaction but doesn't change the position of equilibrium as it speeds up both sides of the reaction.

what is a catalyst

A substance which increases the speed of a reaction, without being changed or used up in the reaction

how does a catalyst affect the rate of reaction?

a catalyst increases the rate of reaction. this is because it provides an alternate reaction pathway with a lower activation energy. more particles will have sufficient energy to overcome the activation energy and react some more successful collisions occur in the same time.

what is a reaction profile?

a graph showing the relative energies of reactants and products, as well as the activation energy of a reaction.

what is an endothermic reaction?

a reaction in which energy is taken from the surroundings.

what is an exothermic reaction?

a reaction in which heat energy is given to the surroundings.

what type of reaction is photosynthesis

endothermic

ammonuim chloride is added to 100cm cubed of water. the temp cahnges form 25*C to 20*C. which reaction occurs.

endothermic.

are precipitation reactions endothermic or exothermic

exothermic

when dilute sulfuric acid reacts with aqeuos sodium hydroxide, the temperature of the solution increases. which words describe this reaction?

exothermic and neutralisation.

if the energy change of a reaction is negative is it exothermic or endothermic?

exothermic- energy has been lost to its surroundings.

in which reaction is the energy absorbed for bond breaking less that the energy released by bond formation?

exothermic.

what are the forward and backward reactions of the thermal decomposition of ammonium chloride

forward reaction breaks down ammonium chloride into ammonia and hydrogen chloride the backward reaction is letting ammonia and hydrogen chloride cool down react and reform to ammonium chloride.

Solutions of two chemicals are mixed. A reaction occurs and the temperature change is measured. Which statement is correct?

id the reaction is endothermic, the temperature decreases and energy is taken in.

how does surface area affect the rate of reaction?

increase the surface area of reactants increases the rate of reaction. this is because a greater surface area means there are more exposed particles so more frequent successful collisions.

how can the rate of reaction be increased.

increase the temp /increase the concentration/ increase the surface area to volume ratio/ increase the pressure (for gasses)/ add a catalyst.

what happens if dymanic equilibrium is disturbed

it will respond by opposing any changes that are introduced

what is a reversible reaction

its a reaction where products can be converted back to the reactants under suitable conditions, it can proceed in both forward and backward reactions.

what must happen for a reaction to occur?

particles must collide at the correct orientation with sufficient energy to react.

When ammonium nitrate is added to water the temperature of the water decreases. The ammonium nitrate can be recovered by evaporating the water added. Which explains these observations?

the ammonium nitrate dissolves in the water and the process is endothermic.

Some white anhydrous copper(II) sulfate powder is put into a beaker of water and stirred. What would show that the process was exothermic?

the beaker feels warmer.

what does the term 'activation energy' mean?

the minimum amount of energy required to occur between two reacting particles.