Reaction Rates and Collision Theory
What happens to the rate of reaction if the temperature is increased?
Rate increases.
What does Le Chatelier’s Principle state?
It states that a system at equilibrium will adjust to counteract changes in concentration, temperature, or pressure.
What state of matter has particles that are closely packed and vibrate in place?
Solid
What is the formula used in calorimetry calculations when there is a change in temperature?
q = mcΔT
(where q = heat, m = mass, c = specific heat capacity, ΔT = change in temperature).
What does a catalyst do in a chemical reaction?
Speeds up the reaction.
Lowers activation energy.
A reaction between powdered and solid reactants: which has a faster rate of reaction?
Powdered reactant reacts faster because of larger surface area
If the concentration of a reactant is increased, what happens to the equilibrium position?
The equilibrium shifts to the right, producing more products.
How do gas particles move compared to liquid particles?
Gas particles move freely and rapidly, while liquid particles are closer together and move more slowly.
If you know the mass of a substance and the change in temperature, what else do you need to calculate the heat absorbed or released?
You need the specific heat capacity of the substance.
What is the effect of increasing the concentration of a reactant on the rate of reaction?
Increasing the concentration of a reactant increases the rate of reaction by making more collisions possible.
How does stirring a solution affect the rate of reaction?
Stirring increase the rate by bringing the reactants together more effectively.
In a reaction at equilibrium, increasing pressure shifts the equilibrium towards which side?
The equilibrium shifts to the side with fewer gas molecules.
When a solid is heated, what happens to the energy and particle motion?
The energy increases, and the particles move faster and farther apart.
What is the specific heat capacity of a substance?
The amount of heat required to raise the temperature of one gram of a substance by 1°C.
What is the difference between an exothermic and endothermic reaction?
An exothermic reaction releases heat, while an endothermic reaction absorbs heat.
Which factor does NOT affect the rate of a chemical reaction: concentration, surface area, or color of reactants?
Color of reactants
If a reaction is exothermic, what happens when the temperature is increased?
It shifts to the left, favoring the reverse reaction.
How do the intermolecular forces compare in a gas versus a liquid?
Gas particles have weak intermolecular forces compared to liquid particles, which have stronger forces.
How do you calculate the heat absorbed by a substance that is melting?
Heat of fusion
Q=mHf
When can a reaction be in equilibrium?
In terms of Collision Theory, what must occur for a reaction to happen?
Proper orientation
In a reaction with multiple products and reactants, adding more product will do what to the reaction?
It shifts to the left, favoring the reverse reaction to decrease the concentration of the product.
When heat is added to a substance, what typically happens to its particle motion and energy?
Particle motion increases, and the energy increases as the particles move faster.
How does the Law of Conservation of Energy apply to calorimetry?
Energy cannot be created or destroyed; it is simply transferred, so the heat released by the system is absorbed by the surroundings.
Is the following reaction endo or exothermic?
2AgCl + energy --> 2Ag + Cl2
endothermic