U10 PT- Aanika & Mckenzie

Chemical rates

Equilibrium

The characteristics of equilibrium is that the rate of the forward reaction has to equal the rate of the reverse reaction

Write equilibrium expressions

Calculate equilibrium constant

Le Chatelier's Principles

calculating reaction rates

Reaction rates: A reaction rate is the speed at which the chemical reaction proceeds. A person can speed up a reaction by increasing the temperature, increasing the concentration, increasing the surface area, and adding a catalyst to the reaction

Rate= k[A]^x [B]^y

the collision theory: reactants must collide with sufficient energy and at the correct angle which determines the rate of the reaction. they must collide with these two things so the bonds can break

describe how changes to the nature of reactants, concentration, temperature, and surface area affect the rate of a reaction

Rate laws: this is a mathematical relationship that is found by comparing reaction rates and reactant concentrations. You are given a table and you need to find the exponents that is after A and B by using this table

rate-determining step: the slowest step in a series of steps as a part of a chemical reaction. Each step will not take place at the same rate

x is the order of the reaction with respect to A

Nature of the reactants: Some substances react ore readily than others

y is the order of the reaction with respect to B

Concentration: When concentrations are increased, there are more particles. Increase the chances of effective collisions

Temperature: The increase in kinetic energy allows for more particles to effectively collide. A decrease in kinetic energy decreases the number of effective collisions

Surface area: Greater surface area allows particles to collide with many more particles per unit of time. Reaction rate increases

Concentration: increasing the concentration of a chemical species will make the equilibrium favor the opposite side. Ex. increasing the concentration of one of the reactants causes equilibrium to favor the products and vice versa. Decreasing the concentration of a chemical species causes the equilibrium to favor the same side. Ex. decreasing the concentration of the products causes the equilibrium to favor the products and vice versa.

Pressure (can only be used when all the chemical species are gases): Increasing the pressure will make the equilibrium favor the side with the smaller number of moles. Decreasing the the pressure causes the equilibrium to favor the side with more moles.

Temperature (requires the Delta H of formation): Increasing the temperature will cause the equilibrium to favor the endothermic reaction. Decreasing the temperature will cause the equilibrium to favor the exothermic reaction. Ex. if the delta H of formation is negative, this means the forward reaction is exothermic, which means the reverse reaction is endothermic. So when the temperaturee increases, equilibrium favors the reverse reaction.

Overall order= x + y

Keq= [C]^c [D]^d / [A]^a [B]^b

[C]^c and [D]^d represents the products, while [A]^a and [B]^b represent the reactants. The exponents represent each chemical species' coefficients in a balanced chemical equation

[C]ᶜ [D]ᵈ / [A]ᵃ [B]ᵇ

Example: hqdefault

example problems:

H2 + N2 ⇌2 NH3

Using this equation above, explain what happens if you increase the concentration of N2?
-If you increase the concentration of N2 then the equilibrium will favor the products side instead of the reactants side

Using the equation above, if the ΔHf= -875KJ/mol explain what reaction the equilibrium will favor when you increase the temperature?
-When you increase the temperature the equilibrium will favor the reverse reaction because the reverse reaction is endothermic.

Compare and contrast Le Chatelier’s principles of concentration and pressure using the balanced chemical equation above... Concentration and pressure both deal with shifts in the equilibrium, but they are both based on different things. If you increase the pressure then the equilibrium favors the side of the balanced chemical equation with fewer moles. If you increase the concentration then it favors the opposite side of the equation. If you decrease the pressure then it favors the side with more moles, and if you decrease the concentration the equilibrium favors the same side that you decreased from. Concentration can be used with any state of matter, but with pressure, all the chemical species must be a gas.

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to get the x and y you need to look at the table that is provided

and do what? this section lacks detail

How do you solve equilibrium problems?