Unit 7 Equilibrium Flashcards
What is the concept of equilibrium?
Chemical reactions can readily go both ways
What does irreversible mean?
reactants can change to products, but the products can not change to reactants
What is chemical equilibrium?
time in which the forward (reactant to products) and reverse (products to reactants) reactions occur at the same rate (speed)
What is a condition of chemical equilibrium in terms of reversibility?
The reaction must be reversible (can go both ways)
Is there an overall change in the concentration of the reactants and products when a reaction is at equilibrium?
there is no overall change in the concentration of the reactants and products
What is the formula for Kc?
k=[products]/[reactants]
What would happen to Kc if the reaction was reversed?
the reciprocal of the equilibrium constant
What would multiplying the chemical reaction do to Kc ?
Kc super subscript to the power of what the reaction is being multiplied by
How do you add chemical reactions?
eliminate species that occur on both sides
What are the units of the equilibrium constant?
Equilibrium constants are unitless
What is Heterogeneous equilibria?
A state of equilibrium where the reactants and products are in different states
What is Homogenous equilibrium?
a state of equilibrium where the reactants and the products are in the same state
Which type of elements are not shown in equilibrium expressions?
Reactants that are pure liquids (water) and solids (gold) are not shown in equilibrium expressions
What is the formula for Kp?
k=(pressure of products)(pressure of reactants)
what is a description of the Kp expression?
the partial pressure of the products raised to the power of their coefficients over the partial pressure of the reactants raised to the power of their coefficients
How to find partial pressure of each species?
number of mols of that species over the total number of moles and multiply that by the total pressure of the system
What is partial pressure proportional to? what is the condition to this?
the number of moles of gas , if the pressure and volume are held constant
what does it mean if kc>10^3?
product side has higher concentration than reactant side
what does it mean if kc<10^-3?
the reactant side has a higher concentration than the product side
what does it mean if 10^-3 <Kc<10^3 ?
there are the same number of moles on both sides of the equations
Which type of reaction does Equilibrium constant expression work for?
equilibrium reactions
How is the equilibrium constant similar to the reaction quotient?
they both take the concentration of the products over the concentration of the reactant, however, the reaction quotient deal with any reactions, not only restricted to reactions at equilibrium
What happens when the equilibrium quotient equals the equilibrium constant?
there is no net reaction (no overall change in the products and reactants) because the reaction is at equilibrium
What happens when the equilibrium quotient is less than the equilibrium constant?
the net reaction (the overall reaction) goes from left to right ( reactants to products)
What happens when the equilibrium quotient is greater than the equilibrium constant?
the net reaction( the overall reaction) goes from right to left (products to reactants)
What is solubility?
the ability of a substance to dissolve
What do ionic compounds do in solutions?
dissociate into ions within the solution they dissolve in
At equilibrium, what are the concentrations of ions like?
concentration of ions is constant
What is a saturated solution?
the maximum amount of dissolved solute a solution can hold at a particular temperature and pressure
what is a unsaturated solution?
when the solution has less solute than the solution is capable of dissolving so the solute can dissolve completely
what is a supersaturated solution?
when a solution contains more than the maximum amount of solute that can dissolve in a solution. the extra solute that can not dissolve will sink to the bottom of the solution forming precipitation
What is the Ksp expression used for?
ion product expression
when can we only calculate Ksp?
when the concentration of products is known
What is nitrogen converted into in the Harber process? what element is used to help with this?
ammonia with the help of H2 help
If stress is put on a reaction solution at equilibrium how will the reaction move?
will move in a direction that relieves the stress
What are stresses that can be applied to a reaction?
changes in concentration, pressure, volume and temperature
Which direction will a reaction move if moles is removed from one side?
reaction to move where the concentration has been removed
Which direction will a reaction move if more moles are added to one side?
the reaction to move where there is less concentration
What will lower volume do to pressure?
increase pressure
What will an increase to volume do to the pressure?
decrease pressure
For an exothermic reaction, how do the equilibrium constant and the temperature change? which way will the reaction move?
equilibrium constant decreases as the temperature increases because heat is on the product side. the reaction will move the reactant side
For an endothermic reaction, how do the equilibrium constant and the temperature change?which way will the reaction move?
The equilibrium constant increases as the temperature increases. The equilibrium reaction is moving from reactants to products
What does the amount of reactant and products depend on?
the energy of the reactants and products
What do catalysts not affect?
the position of the equilibrium
Do the equilibrium mixture of reactants and products occur faster or slower when a catalyst is added to the reaction?
faster
What do catalysts do to the activation energy? Do they get used up during this process?
lower the activation energy without being used up
