Answer to Question #162160 in General Chemistry for kyle

Question

1.      Equal amounts of two types of waste are disposed into a section of a landfill. They both start producing gas at t=0, so there is no lag time. Assume first order decay for gas production. Each type of waste can produce 150 L methane per kg of waste. Waste A produces gas with a half-life of 6 years, and waste B produces gas with a half-life of 3 years. How long until 90% of each gas has been produced?

Answer 1

After each half life period we get half of the amount.

After 3 half life 87.5% (can say around 90%) of gas will be produced

Time After 3 life = 6 x 3 = 18 years for gas A.

Time After 3life = 3x3 = 9 years for gas B.