The opposite type of reaction (where energy is taken in from the surroundings of a reaction and thus the energy of the reactants is lower than that of the products) is called an endothermic reaction
I would say that Niven would have to calculate the atomic weights of Mg and O and then the total weight of MgO to get the percent of oxygen and then that way get a proportionate amount of the 28 grams of oxygen required to bond with the Mg and then add together the weight of Mg which would be 28.0 grams plus the weight of oxygen.
Answer is: 12,6% (1/8) <span>percentage of the sample will remain.
</span>c₀ - initial amount of C-14.<span>
c - amount of C-14 remaining
at time.
t = 5700</span> y.<span>
First calculate the radioactive decay rate constant λ:
λ = 0,693 ÷ t = 0,693 ÷ 5700</span> y = 0,000121 1/y = 1,21·10⁻⁴ y.
c = c₀·e∧-λ·t.
c = 2000 · e∧-(0,000121 1/y · 17100 y).
c = 252 g.
ω = 252 g ÷ 2000 g = 0,126 = 12,6%.
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