The half-life of a first order reaction is determined to be 85.5 years. How long will it take for the concentration of the reactant to reach 2% of its initial value?

the correct answer is 536 years (green check!!)

had a red x !!! the answer is not 536!

i have the green check!

you have to write only 536 in the box!

Did it with 536 and still red X. must be a system error.

Actually its 443

Another red X for 443

The years value is diferent, I got the green on 536

That could be the reason. Use the method used in H6P5.

I am in agreement, because there are other questions whereby the years is 90.2, anyway could anyone give a step by step method in answering the above question?

The values are different for every person - its an anti-cheat system.