Chapter 17 Chemistry
if doubling the concentration of a reactant quadruples the rate of the reaction, what is the exponent of the concentration of the reactant in the rate law
1
think of the conditions that speed up reactions. when considering surface area, which would burn most slowly a. a large lump of coal b. small pieces of coal c. powdered coal d. all of these burn at the same rate
A. a large lump of coal
How does changing the temperature affect the rate of reaction?
It affects the frequency of collision and the number of effective collisions
If a reaction system has come to equilibrium, it can be made to run to completion under what circumstances?
The product has precipitated as a solid
What is a homogeneous reaction
a homogeneous reaction is a reaction in which all of the reactants and products are in the same phase
what does the letter k in a rate law stand for
a proportionality constant
when the chemical equilibrium expression is written, coefficients from the equation for the reaction become what part of the expression
appear as exponents
at equilibrium, what is happening/ has happened to the forward and reverse reactions
both the forward and reverse reactions continue
how is the reaction order found
by adding the reaction orders with respect to the reactants
Which process is used to speed up chemical reactions
catalysis
what does concentration rate depend on
concentration
what affects reaction rate
concentration of reactants, temperature, the physical state of reactants and their dispersion, the solvent, and the presence of a catalyst
A sample of a substance burns more rapidly in pure oxygen than in air. Which factor is most responsible for this high rate of reaction?
concentration of the substance
reactions tend to run to completion if a product has what propertiess
gas
which term describes a catalyst in the same phase as the reactants and products
homogenous
under what conditions do reactions tend to run to completion
if the product is precipitated as a solid
what does raising the temperature of reactants in a system do to the average kinetic energy of the molecules and the collision rate of the molecules
increases the average kinetic energy of the molecules
how is a heterogeneous catalyst different from the reactants in a chemical reaction
it has a different phase from that of the reactants
If the concentration of reactants is higher, how is the reaction rate affected
it increases
under suitable conditions, roughly what proportion of all chemical reactions are reversible
nearly all
What does a very high value of K indicate
products are favored
catalysts generally affect chemical reactions by doing what
providing an alternate pathway with a lower activation energy
What does a very low value of K indicate
reactants are favored
what does the letter n in a rate law stand for
reaction order
what does the letter R in rate law stand for
reaction rate
what is the decrease in reactant concentration per unit time in a reaction a measure of
reaction rate
what does a rate law relate
reaction rate and concentrations of reactants
what kind of reaction occurs in which products can react to re-from reactants
reversible reaction
at equilibrium, how do the rates of the forward and reverse reactions compare/ differ
the forward reaction rate is equal to the reverse reaction rate
in a chemical equation, what part becomes the numerator when calculating the equilibrium constant
the products
what is rate
the rate at which a chemical reaction takes place; measured by the rate of formation of the product or the rate of disappearance of the reactants
in a chemical equation, what part becomes the denominator when calculating the equilibrium constant
the reactants
if the temperature of the reactants is low how is the reaction rate affected
the reaction rate is generally lower
what does a value of K near 1 indicate
there are roughly equal concentrations of reactants and products
In heterogeneous reactions, what is different about the reactants
they are in different phases
according to the rate law, how are the rate of a reaction and the concentration of reactants related
they are proportional
what must occur in order for gas particles to react
they must collide
