Rate of reation Flashcards
explain the effect of surface area on reaction rate
An increase in surface area can result in a higher chance of collisions so the number of effective collisions increases.
describe methods to follow the progress of the reaction
Measure the volume of gas given out by a syringe
Measure the change in mass of the reaction mixture by an electronic balance
Measure the change in pressure over time by a pressure sensor in a closed system
why is it necessary to make the total volume the same in different trials when varying concentration
to ensure fair comparison between trials
the volume of the solution used can represent the concentration of the solution in the reaction mixture
what is instantaneous rate
the rate at a particular instance of the reaction is called the instantaneous rate
describe the characteristic of a rate curve (conc vs time)
at the beginning the slope is the steepest, the rate of reaction is faster. Its because the concentration of the reactant is higher
at the intermediate stage , the slope is less steep than the beginning, the rate of reaction is slower. It is because some of the reactant is used, the concentration of reactant is lower
at the end, the slope is equal to zero, it means that the rate is equal to zero. It is because the reactants is used up completely
how to quench a solution
rapid cooling by addition of ice
diluting with cold water
what are the disadvantages of using titrimetric analysis to follow the progress of a reaction
it is very difficult to monitor the change of concentration continuously
it cannot be used to study fast reactions because titrimetric analysis takes time
what is the advantage of using a data-logger
it can collect and store data over very short time intervals.
The data-logger can record hundreds of readings for more accurate analysis at a later time
This is impossible or impractical for a human operator
what is the use of cotton wool in the experiment setup of following the progress of a reaction by measuring the change in mass of the reaction mixture
to avoid splashing out of the solution, but allow the escape of CO2
how the color of filter in colorimeter is selected
a filter is used to select the light which the coloured species absorbs the most. The filter has a colour complementary to the colour of the coloured species
red and green
orange and blue
yellow and purple
what is the advantage of using colorimetrey in rate experiment
the readings can be instantly obtained
concentration of coloured chemical need NOT be high
what is the requirement for a reaction to occur
have sufficient amount of energy
collide in the right direction
explain the effect of surface area on reaction rate
when size decrease surface area per unit mass of solid reactant increases contact between reactants increases number of effective collisions increases reaction rate increases
why antacid should be well chewed before swallowing
to increase surface area for faster reaction with HCl
explain the effect of temperature on reaction rate
when temperature increases average kinetic energy of reactant particles increases reactant particles move faster frequency of collision increases number of effective collisions increases reaction rate increases
