speed of reaction Flashcards
how to measure s.o.r.?
1) measure volume of gas produced
necessary apparatus: stopwatch and gas syringe
as the reaction takes place, the amount of gas collected in the gas syringe increases
2) measure the mass of the reactant that remains
necessary apparatus: stopwatch and electronic mass balance
as the reaction takes place, more gas is being produced and escaping the conical flask. hence the mass of the system decreases overtime.
the steeper the graph?
the faster the speed of reaction
the gentler the graph?
the slower the speed of reaction
when the graph is horizontal (x=0)?
the reaction has completed
what makes an effective collision?
for the reaction to occur, the particles must collide with each other and have energy equal to or greater than the collision energy
what is the result of an effective collision?
products will be formed
what affects the speed of a chemical reaction?
the frequency of effective collisions between reactant particles
how does temperature affect the sor?
at higher temperatures, the particles have higher kinetic energy and will collide more frequently. more particles will have energy greater than or equal to the activation energy. this increases the frequency of effective collisions and hence, increases the sor.
how does the size of solid reactants affect the sor?
when the particle size of the reactants decreases, the exposed surface area for collision to occur increases. this increases the frequency of effective collisions and hence, increase the speed of reaction.
how does concentration affect sor?
at higher concentrations, particles are closer together and the number of reactant particles per unit volume increases. this increased the frequency of effective collisions, hence increasing the sor.
when excess acid is used, concentration affects sor only
if acid is the limiting reactant, concentration affects sor and vol of gas produced
how does pressure affect sor?
pressure has little effect on reactions involving solids and liquids. however, in reactions with gaseous reactants, the higher the amount of pressure, the higher the sor. at higher pressure, the particles are closer together and this increases the number of reactant particles per unit volume. this increases the frequency of effective collisions, hence increasing the sor.
what are the factors that affect sor?
concentration, temperature, particle size and pressure
what ate factors that affect the volume of gas produced?
mass of limiting reactant and conc of limiting reactant
