How much of an 800-gram sample of potassium-40 will remain after 3.9 x 109 years of radioactive decay?

Ans: Amount of K-40 remaining = 92.2 g

Given:

Initial mass of potassium-40 = M₀ = 800 g

Time, t = 3.9 *10⁹ years

To determine:

The mass of potassium-40 (M(t)) that will remain after time 't'

Explanation:

The radioactive decay equation is given as:

----(1)

where t1/2 is the half-life of K-40 = 1.251*10⁹ years

Substitute for M₀, t and t1/2 in equation(1):

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2

the awnser is group 12