You want to test how the mass of a reactant affects the speed of a reaction. Which of the following is an example of a controlled experiment to test this?

A) The mass of all the reactants is kept the same, and the mixtures are allowed to react for different amounts of time

B)The mass of all reactants is varied, and the time it takes the reaction to finish is measured

C)The mass of one reactant at a time is varied, and the time it takes one reactant to finish is measured

D)The mass of one reactant and the temperature of the reaction mixture are increased until reaction is finished

answer is a

explanation:

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.