Which substance is the BEST example of a compound?
1 answer:
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A. The radioactive decay equation is N = N0
where T is the half-life (5730 years), N0 is the number of atoms at time t = 0 and N is the number at time t.
Rewriting this as:
(N/N0) =
Since N = (1/8) N0 and substituting known values:
1/8 =
Taking ln of both sides:
ln(1/8)= -ln(2)*t/5730
t = - 5730 * ln(1/8) / ln (2)
t = 17,190 years
The tree was cut down 17,190 years ago.
B. N0 = 1,500,000 carbon-14 atoms
Since N = (1/8) N0
N = 187,500 carbon atoms left
Answer:
There are 0.00523 moles of oxygen in 0.150 grams of calcium sulfate crystal.
Explanation:
Mass of calcium sulfate crystal = m = 0.150 g
Molar mass of calcium sulfate crystal = M = 172 g/mol
Moles of magnesium nitrate = n
1 mole of calcium sulfate crystal has 6 moles of oxygen atoms. Then 0.004446 moles calcium sulfate crystal will have :
There are 0.00523 moles of oxygen in 0.150 grams of calcium sulfate crystal.