equilibria, rate of reaction Flashcards
what is exothermic reaction
release thermal energy, surrounding heat up
what is endothermic reaction
take in energy, surroundings cool down
enthalpy change in endo and exo reactions
in exo its negative, endo is positive
what is the transfer of thermal energy during a reaction called?
enthalpy change
what is activation energy
the minimum energy that colliding particles must ave to react
endo and exo in terms of bonds
endo is in bond breaking, in which energy is used to do so and exo is in bond making, no energy is needed to make bonds
what is the law pf energy to break or make bonds
always same amount of energy needed to produce or make bonds
what does this symbol represent? ⇌
reversible reaction, occurs in both the forward and backward direction
what happens if forward reaction is exo
backward is endo
what colour change occurs if anhydrous copper sulfate was added to water
white to blue
what colour change occurs in anhydrous cobalt chloride was added to water
blue to pink
what is dynamic equilibrium
Revirsable reactions that take place in a closed system
-the forward and backward reactions occur at same rate
-the concentrations of reactants and products are no longer changing
what is the process to reach dynamic equilibrium
at start there are reactants only no products,
rate of reactants being used up increases and rate of products being used up decreases
rate of forward and backward reaction is the same
what happens to rate of reaction if temperature increases
The rate of reaction is faster/ increases because kinetic energy is given to molecules therefore increasing the number of collisions per second
the particles gain more energy and move faster. This means that they collide more often. If the temperature is decreased, the particles have less energy, move more slowly and collide less often
what happens to the position of equilibrium when temperature increases
shifts to the endothermic side
what happens to the position of equilibrium when temperature decreases
shifts to the exothermic side
what happens to the position of equilibrium when we increase concentration
position shifts to the opposite side in which the concentration was increased to balance the equation again
what happens to rate of reaction if we increase pressure
increases rate of reaction because there are more molecules per centimeter cubed therefore there are more collisions per second,
the number of particles in a given volume also increases an so the rate of reaction increases.
what happens to the position of equilibrium once we increase pressure
shift to the side with less molecules
what happens to the position of equilibirum if a catalyst is added
forawrd and backward reaction are sped up however there is no effect on position
what is the symbol equation for the production of ammonia in the haber process
N2(g) +3H2(g) <–>2NH3(g)
what are the sources of hydrogen and nitrogen in the Haber process
hydrogen- methane
nitrogen- air
what are the typical conditions in the Haber process
450 celsius
20000kPa/200 atm
iron catalyst
what is the symbol equation for the conversion of sulfur dioxide into sulfur trioxide in contact process
2SO2(g) + O2(g) <—> 2SO3(g)
what are the sources of sulfur dioxide and oxygen in contact process
sulfur dioxide- burning sulfur or roasting sulfide ores
oxygen- air
what are the typical conditions for the conversion of sulfur dioxide to sulfur trioxide int he contact process
450 celsius
200kPa/2atm
vanadium oxide catalyst
what is used as fertilisers
ammonium salts
nitrates
what is the use of NPK fertilisers
to provide the elements nitrogen phosphorus and potassium for improved plant growth
what happens to rate of reaction when you add a catalyst
increases, the rate of reaction in both forward and backward directions by providing an alternate pathway with lower activation energy
what happens to rate of reaction when you increase concentration
the rate of reaction increases the frequency of collisions between reactants and will, therefore, increase the reaction rate, increased chance in succesful collisions
describe collision theory in terms of number of particles per unit volume
bigger number of particles more collisions
and vice versa
describe collision theory in terms of changing pressure of gas
bigger pressure of gas means greater number of collisions
describe collision theory in terms of kinetic energy of particles
greater kinetic energy means more collisions, because particles move faster therefore more collisions per sec
describe collision theory in terms of activation energy
every reaction to start, the molecules need an activation energy so that there are collisions. there must be sufficiently energetic collisions t break chemical bonds
what is the effect on rate of reaction by changing surface area of solids
When solids react, the reaction occurs on the surface of the substance. If there is more surface area exposed, then this will increase the rate of reaction. You can increase the surface area by making the size of the particles smaller.
what happens to rate of reaction by adding or removing a catalyst, including enzymes using collisions theory
A catalyst is a substance that speeds up the rate of a reaction but it does not get used up in the reaction. As a catalyst does not get used up in the reaction, they can be reused or recycled.
enzymes, which are biological catalysts. They increase the rate of biochemical reactions – for example, respiration in our bodies. They work best at an optimum pH and temperature. If the temperature is too high or if pH is too extreme, enzymes can lose their structure and be denatured (destroyed). Once an enzyme is denatured, it will not work anymore
what do catalysts do to activation energy
they decrease it
what are practical methods for the investigation of rate of reaction
to show how concentration changes the rate of reaction, you can conduct an experiment in which you change the concentration or mass used of a reactant and measure the time it takes for a colour change to happen, or measure the amount of gas produced with a syringe to be more precise.
what is the name of the process that produces ammonia
haber process
what is the name of the process that produces sulfuric acid
contact process
describe the contact process
sulfur is turned into sulfur dioxide by burning in air (exo)
then sulfur dioxide is turned into sulfur trioxide by mixing it with more air and passed over beds ov vanadium oxide catalyst
thent sulfur trioxide is dissolved in concentrated sulfuric acid to turn into a thick fuming liquid called oleum (h2s207)
and lastly oleum is added to water and turns into concentrated sulfuric acid
