Awooden boat is discovered just south of the graet pyramid in egypt had a carbon-14 content of approximately 25% of that found in living organisms. how old is the boat? (the half-life of carbon-14 is 5,715 years.)

Because 25% is half of 0.5 and the half life of is given as 5,715, the time it takes to reach this amount should just be double the half life: 11430 years.

However, in other cases the problem may not have easy numbers, so below is a more mathematical approach.

The half life formula is .

Solving for t gives:

Given information:

Plug in given values and solve for t.

With correct significant figures, this would be 11000 years.

"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"