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
If the formula for density=m/v, you can manipulate this formula to the the mass. After manipulation, you get the equation for mass to be: m=density * volume. With density and volume given, we can find the mass.
mass= (8.9) * 6 = 53.4grams
Answer:
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Explanation:
The order of boiling point depends upon the type of interactions present between the molecules.
Potassium fluoride (KF) is an ionic compound and the opposite ions are held together by strong electrostatic forces.
is a covalent compound and the molecules are held together by weak van der Waals' forces.
Formaldehyde is a polar compound due to presence of polar carbonyl group. Hence dipole-dipole force is present between formaldehyde molecules.
Thus the decreasing order of boiling point is:
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Answer:
B the rides are to the sun

a)



b)


Using the atomic mass given in the periodic table:




c)


Using the atomic mass given in the periodic table:




This result is an aproximation.