The rate constant for a first order reaction with a single reactant is 7.54x10-4 s-1. If the initial reactant concentration is 1.18 M, what will the reactant concentration be after 8.30 minutes?

Answer : The reactant concentration be after 8.30 minutes is, 0.812 M

Explanation :

Expression for rate law for first order kinetics is given by:

where,

k = rate constant  =

t = time passed by the sample  = 8.30 min = 498 s

a = initial amount of the reactant  = 1.18 M

a - x = amount left after decay process = ?

Now put all the given values in above equation, we get

Therefore, the reactant concentration be after 8.30 minutes is, 0.812 M

hope this !

explanation:

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.