The isotope carbon-14 decays over time into nitrogen-14 with a half-life of 5,730 years. Suppose that you find a fossil that contains 1.25 grams of carbon-14 and 3.75 grams of nitrogen-14. How old is the fossil

11460 years

Explanation:

0.693/t1/2 = 2.303/t log (No/N)

t1/2 = half life of the carbon

t = age of the fossil

No= amount of radioactive material originally present

N= amount of radioactive material present at time=t

No= mass of carbon + nitrogen = 5g

0.693/5730 = 2.303/t log (5/1.25)

1.21 ×10^-4 = 1.3866/t

t= 1.3866/1.21 ×10^-4

t= 11460 years

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

the volume increases