To calculate atomic mass, you have to take to weighted average of the isotopes' masses. What that means is M = RA*106 + (1 – RA)*104, where RA is relative abundance expressed in decimal form. If you simplify the right side of that equation, you get M = 2*RA + 104. Doing a little more algebra yields RA = (M –104)/2 = (104.4 – 104)/2 = 0.4 / 2 = 0.2, which is 20%. So the answer is B.
Jill and Susan violated safety procedures by not properly listening and/or reading over the instructions to know all the materials, steps, and equipment they need for the lab. Hope this helps!
Answer : The volume of the cube is, 
Solution : Given,
Density of nickel = 
Number of nickel atoms = 
Molar mass of nickel = 58.7 g/mole
First we have to calculate the moles of nickel.
As,
atoms form 1 mole of nickel
So,
atoms form
moles of nickel
The moles of nickel = 3.321 moles
Now we have to calculate the mass of nickel.


The mass of nickel = 194.94 g
Now we have to calculate the volume of nickel.



Therefore, the volume of the cube is, 
If you start with 40.0 grams of the element at noon, 10.0 grams
radioactive element will be left at 2 p.m. The correct answer between
all the choices given is the second choice or letter B. I am hoping that this
answer has satisfied your query and it will be able to help you in your
endeavor, and if you would like, feel free to ask another question.
The sun's energy would be circulated through convection. This is because whenever you see the word "circulate", there is a pretty good chance it has something to do with convection.