speeding up our chemistry
(reaction rates)
(reaction rates)
Fill in the blank:
a ____ substance does not undergo spontaneous changes under the surrounding conditions
Stable
Define what equilibirum is
the exact balancing of two processes, one of which is the opposite of the other
or
the reaction is going forwards and in reverse at the same rate.
Define what pH is in under 10 words
concerntration of hydrogen ions
the amount of heat energy needed to change a substance from a solid into a liquid at a constant temperature
What can a proton also be written as?
H+
Name atleast one assumption that you would need to consider when looking at reaction mechanisms
•reactant particles must collide in order for a reaction to occur
•particles must collide with a minimum total amount of energy if the collision is to result in a reaction
•sometimes particles must be oriented in a specific way for a reaction to occur
Define K in this equation.
the ratio of the equilibrium concentrations of products and reactants, taking into account the stoichiometry
The size of K tells you how far the reaction will proceed
what units does pH have?
none
Calculate the heat required to melt 20g of ice at 0C
Remember:
Heat of fusion for water is 335 J/g
Define an acid in the Brønsted theory
Any hydrogen containing substance that donates a proton to another substance
What is Activation energy?
the minimum amount of energy required to start a reaction
what does the square brackets [] mean in the equilibirum expression
concerntration
what is the pH of this:
[H3O+] = 1 x 10-11 mol L-1
pH=11
Calculate the heat required to heat the 20g water from 0C to 100C
remember:
Specific heat of water is 4.184 J/g·°C
8368J
Find the conjugate acid-base pair:
HCl(aq) + H2O(l) <-> H3O+(aq) + Cl-(aq)
HCl(aq) and H3O+(aq)
or
H2O(l) and Cl-(aq)
Name 2 factors influencing the speed of reactions
1. nature of the reactants
2. concerntration of particles
3. temperature
4. catalysts
write the equilibrium expression for the following:
2SO2(g) + O2(g) ↔ 2SO3(g)
placehold will write on zoom
What [H+] is a solution with a pH of 5.92?
1.2 x 10-6 mol L-1
Calculate the heat required to convert the 20g water to steam at 100C
Heat of vaporisation for water is 2259 J/g
45180J
define a strong acid:
a chemical that completely breaks apart into ions in water to release hydrogen ions.
Explain what a catalyst does to a reaction and provide an example of one
they lower the activation energy fo a reaction, making it easier and quicker for a reaction to occur. an example includes enzymes
A mixture of the gases NOCl, Cl2 and NO is allowed to reach equilibrium at 25 °C. The measured equilibrium concentrations are [NO] = 0.92 mol L–1, [NOCl] = 1.31 mol L–1, and [Cl2] = 0.20 mol L–1. What is the value of the equilibrium constant at 25 °C for the reaction:
2NOCl (g) ↔ 2NO(g) + Cl2(g)
k=0.099
Find the [H3O+] of a water solution when pOH = 7.8
1.58x10-8 mol/L
6.3x10-7 mol/L
Calculate the total amount of energy required to heat 9 kg of ice at −20 °C all the way to 120 °C water vapour
2.79x107
fill in the blanks
In an _____ solution [H3O+] > [OH-]
In a _____ solution [H3O+] < [OH-]
Acidic and basic