Unit 1 Flashcards
(36 cards)
Reaction Rate Formula?
Difference in amount/Difference in Time
Which properties can be monitored to discover the reaction rate?
Colour change, temperature change, pressure change, mass change, change in pH.
How do you measure colour?
Spectrophoto meter
How do you measure Temperature change?
A thermometer to measure temperature.
Line of best fit? Otherwise known as?
Line that goes through atleast two points of reference. A tangent line.
Why is pressure NOT a good property to monitor this equation: H2(g) + Cl2(g) -> 2HCl (g)?
2 mol of gas used per 2 mol of gas produced therefor not pressure changes occur
What are 6 factors that affect reaction rates?
Temperature, concentration, pressure, ability for reactants to meet; surface area and phase considerations, nature of reactants, catalysts
What effect does temperature have on reaction rates?
Increasing temperature increases the reaction rate.
Why does temperature increase the reaction rate?
have more kinetic energy (move faster) so they collide more often and have sufficient energy to react.
What effect does pressure have on reaction rates?
As the volume decreases, the pressure increases, therefor the reaction rate increases
Why does pressure increase the reaction rate?
The molecules are closer together giving more opportunity for a reaction.
What effect does concentration have on the reaction rate?
higher concentration of reactant particles increases the reaction rate.
Why does concentration of reactant particles increase the reaction rate
reactant particles have a higher probability of reactions w/ eachother rather than the solvents
What effect does the ability for reactants to meet have on the reaction rate?
The greater the surface area, the greater the reaction rate. liquid reactants react faster than solid reactions.
why does the ability for reactants to meet increase the reaction rate?
more surface area means more available locations for reactants to meet. gas & liquids move more freely w/ eachother. dissolved ions have the benefit of strong positive-negative attractions.
what effect does the nature of the reactants have on the reaction rate?
when bonds are weak and electrons are easily shared, reactions occur more quickly.
Why does the nature of the reactants increase the reaction rate?
Some reactions are faster because the bonds being broken are weak and electrons are easily shared.
What effect do catalysts have an the reaction rate?
they are a chemical which increase the reaction rate while not being consumed in the overall reaction.
why do catalysts increase the reaction rate?
it speeds things up by offering an alternative reaction mechanisms w/ a lower activation energy.
What is the difference between a heterogeneous and homogeneous reaction?
heterogeneous: reactions where the reactants are in different phases ex. gas/liquid
Homogeneous: reactions where the reactants are in the same phase ex. Gas/gas.
define a catalyst
A chemical which increases the rate of the reaction while not being consumed.
What is one factor that affects only the rate of heterogeneous reactions. Why does it not affect homogeneous reaction rates?
Surface area; there is no concept of surface area when a mixture is homogeneous
Define Kinetic Energy
the energy of motion. anything that is moving has kinetic energy
What is the importance of the Kinetic Molecular Theory (KMT)?
The only theory available that accurately predicts macroscopic properties of gas like temperature, pressure and thermal expansion by considering their molecular composition and motion.
