When formic acid is heated, it decomposes to hydrogen and carbon dioxide in a first-order decay:
HCOOH(g) →CO2(g) + H2 (g)
The rate of reaction is monitored by measuring the total pressure in the reaction container.
Time (s) . . . P (torr)
0 . . . . . . . . . 220
50 . . . . . . . . 324
100 . . . . . . . 379
150 . . . . . . . 408
200 . . . . . . . 423
250 . . . . . . . 431
300 . . . . . . . 435
At the start of the reaction (time = 0), only formic acid is present. What is the formic acid pressure (in torr) when the total pressure is 356? Hint: use Dalton's law of partial pressure and the reaction stoichiometry.