5.1-5.3 Quiz Flashcards
How does volume affect the rate of a reaction?
A decreased volume causes the particles to be closer together which increases the likelihood of effective collisions and increases the reaction rate
Reduced
Gain of electrons, number gets lower
What is the “k” value in rate law dependent on?
It is dependent on temperature and is different for each reaction and set of conditions
What does [A]0 mean?
Initial concentration
How do you solve for rate of reaction?
Use the mole ratio
How does reactant temperature affect the rate of a reaction?
Higher temperature means the particles are more likely to collide with energy greater than the activation energy
What things must happen for a reaction to take place AKA collision theory?
Particles must
- Collide
- With the right orientation
- With energy greater than the activation energy
How do you solve for rate of (dis)appearance?
Disappearance will be negative
Appearance will be positive
You need to use the mole ratio from the balanced equation
Catalyst
They increase reaction rates without being used up and they decrease the energy needed
Why would a rate be negative?
This would be because the amount is decreasing or being used up
How do heterogenous catalysts speed up reactions?
They are different phases than the reactants. They alter the orientation of the molecules for more effective collisions
What do the half-lives for a first order reaction do?
They remain constant
What are the k units for an 1 order problem
1/ time
What are the k units for an “n” order problem
1/ M(n-1) time
What do the half-lives for a second order reaction do?
They increase
When solving for the “k” value and there is a coefficient in front of the product what should you do?
Include that factor in your rate. Ex: If there is a 2 in front of your product, cut the rate provided to you in half, and then solve for k normally.
What do the half-lives for a zero order reaction do?
They decrease
What determines the overall reaction order?
The sum of the exponents
Which equation is used for second order(on equation sheet, just be able to point it out)?
1/ [A]t- 1/[A]0= kt
How do you create rate law with three reactants and experimental data?
Make sure two out of three reactants are constant when trying to determine order
How does reactant surface area affect the rate of a reaction?
More surface area increases the chance of the particles colliding; note: something chopped into fine pieces rather than big blocks of something is more surface area
How do homogenous catalysts speed up reactions?
They are catalysts in the same phase as the reactants. They provide an alternate pathway to complete the reaction and it takes less activation energy
What does half-life tell us about the k value?
The shorter the half-life, the higher the value of k is
Which equation is used for zero order(on equation sheet, just be able to point it out)?
[A]t- [A]0= -kt
If you are asked about the rate of reaction and feel like you don’t have any information about it, where do you look?
Look at reactants with no coefficients or in first order in the rate law because they are directly proportional to the rate
Average Reaction Rate formula
Final- Initial Concentration/ Final- Initial Time
How do you solve for k in a second-order equation with just data?
Use the equation on the equation sheet. Then, when you get to ln(x)= numbers, do e^numbers= x
What does [A]t mean?
Concentration at a specific time
How does reactant concentration affect the rate of a reaction?
The higher concentration increases the chance of a collision because more molecules equals more collisions
Oxidized
Loss of electrons, number gets higher
What do you need to remember about the rate of reaction?
The rate of reaction is always going to be positive
Which equation is used for first order(on equation sheet, just be able to point it out)?
ln[A]t- ln[A]0= -kt
When you are writing a rate of reaction equation what will your A and B values always be?
Reactants
When shown multiple graphs and asked to pick the right one what should it look like?
It will be linear, so just look at the y axis to determine what order it is. Second order will always have a positive slope.
What are the k units for a 0 order problem?
M/ time
How to determine the orders when more than one variable changes?
Experiment blank= Rate2= k2 times [A][B]/
Experiment blank= Rate1= k1 times [A][B]
When looking at graphs and trying to determine the order, how do you determine the correct one?
Zero order will be linear.
First order will have a constant half-life.
Second order will not be linear or have a constant half-life.
What is the slope of a 2nd order equation?
k
How do you solve a half-life equation that is first order?
First solve for k. Then plug it in the equation on the equation sheet.
What is the slope of a 0 and 1 order equation?
-k
What are they looking for when asking for half life from a graph?
An amount of time; If every 8 days the amount cuts in half, the half life is 8 days.
What type of equation is always first order?
Nuclear or radioactive decay
How do you solve for the “k” value when you have a rate law but no rate of reaction?
If the equation is first order use the half-life equation available on the equation sheet. Then use the half-life (_ days/hours/sec, etc.) available.
