Posted by Steve on .
The decopostion of formic acid follows firstorder kinetics.
HCO2H(g)==>CO2(g) + H2(g)
The halflife for the reaction at 550 degrees Celsius is 24 seconds. How many seconds does it take for the formic acid concentration to decrease by 75%?

Inorganic chemistry 
DrBob222,
Calculate k = 0.693/t(1/2) = 0.693/24
Then ln(No/N) = kt
No = 100 to start (any number will do)
N = reduced by 75% so N = 25?
Plug in N, No, and k, solve for t.
Post your work if you get stuck.