sorry I don't know just kidding I know just kidding I don't know
The atomic mass of K is 39
from Avogadro's law
39g of K contains 6.02x10^23 atoms
therefore if
39=6.02x19^23
X=5.11×10^22
making X the subject of the formula
X= (5.11×10^22×39)÷6.02×10^23
X= 33g
Answer: 362,07 cm3
To answer this question you need to convert the lb into gram first. One lb equal to 453.592g, so: 3.6lb x 453.592gram/lb= 1632.9312gram.
Now we have mass(1632.9312g), density (4.51g/cm3). Volume is mass divided by density. The equation would be:
Volume= mass/density
Volume = 1632.9312gram / (4.51g/cm3)= 362,07 cm3
Answer: It will take 29 years for a 10.0-gram sample of strontium-90 to decay to 5.00 grams
Explanation:
Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Half life is represented by 

= rate constant
Given : Strontium-90 decreases in mass by one-half every 29 years , that is half life of Strontium-90 is 29 years.
As half life is independent of initial concentration, it will take 29 years for a 10.0-gram sample of strontium-90 to decay to 5.00 grams as the amount gets half.