it will give half less of the total amount .
From km 240 to km 300 there are 60 km.
The time to travel 60 km at 80km/h is t = d/V = 60km / 80 km/h = 3/4 h.
That is 45 minutes. Then the car will arrive at 7:30 + 45 min = 8:15.
After a chemical reaction, the atomic nuclei are unchanged. (C)
The nucleii don't know a thing about the outside world during
physical or chemical processes ... not until NUCLEAR things
happen.
I would say that the apmosphere would change and we probley would die that's my guess