a) To find the mass after t years:we will use this formula:
A = Ao / 2^n when A =the amount remaining
and Ao = the initial amount
and n = t / t(1/2)
by substitution:
∴ A = 200 mg/ 2^(t/30y)b) Mass after 90 y :by using the previous formula and substitute t by 90 y
A = 200mg/ 2^(90y/30y)
∴ A = 25 mgC) Time for 1 mg remaining:when A= Ao/ 2^(t/t(1/2)
so, by substitution:
1 mg = 200 mg / 2^(t/30y)
∴2^(t/30y) = 200 mg by solving for t
∴ t = 229 y
Answer:
8.3028894e-22
Explanation:
5x10^2 atoms/1 x 1 mol/6.022x10^23
there are 6 moles of oxygen in Zn(No3)2
Explanation:
The number of moles of solute present in liter of solution is defined as molarity.
Mathematically, Molarity = 
Also, when number of moles are equal in a solution then the formula will be as follows.

It is given that
is 8.00 M,
is 7.00 mL, and
is 0.80 M.
Hence, calculate the value of
using above formula as follows.



= 70 ml
Thus, we can conclude that the volume after dilution is 70 ml.
Neither it's a single replacement equation