Zirconium cannot be broken down by a chemical change, because it is an element. The others are all molecules.
In order to solve this, we need to make use of Hess' Law.
We are already given the equations and their corresponding deltaH. Using Hess' Law, we can generate this equation:
104 kJ = x - (-1182 kJ) - (-1144 kJ)
Among the choices, the answer is
<span>B.104 = x - [(-1182) + (-1144)]
</span>
<span>4.999999999999999e</span>+<span>24 this is what i got on the calculator but i dont know if its right.</span>
Answer:
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Equation for Half life :
A = a(0.5)^(t/h)
A is current amount, "a" is initial amount, h is halflife, t is time
5 = 40(0.5)^(t/1.3x10^9)
5/40 = (0.5)^(t/1.3x10^9)
take the log of both sides , power rule
Log(5/40) = (t/1.3x10^9) * Log(0.5)
(1.3x10^9) * Log(5/40) / Log(0.5) = t
3.9x10^9 years = t
And if you think about what a half life is, the time it take for the amount to reduce to half.
40/2 = 20
20/2 = 10
10/2 = 5
It went through 3 half-lifes
3 * 1.3x10^9 = 3.9x10^9 years
