Carbon decays every 5700 years. If you found a rock containing Carbon that has gone through 2.5 half lives, how old is that rock?

14,250 years old.

Explanation:

First, multiply the two lifetimes. - 11,400.

Then, divide 5,700 in half for the 0.5 lifetime. - 2,850.

Lastly, add them all up. - 11,400 + 2,850 = 14,250 years old.

sorry if incorrect <3

thats what i understood XD

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"