Answer: 0.059M
Explanation: time.
t = 19minutes
t = 19 × 60 s
t = 140s
k = n/delta t
(where n is the ratio of change in concentration while delta t is the change in time)
k = n/dt = 6.30×10−3 s−1
6.30×10−3 s−1 = dc/140s
n = 6.30×10−3 s−1 × 140s
n = 882 ×10−3
= 0.882
Concentration of reactant used in forming a product in the reaction after 19 minutes =
n × concentration
0.882 × 0.5 = 0.441M
Reactant concentration
= (0.5 - 0.441)M
= 0.059M