10% of 120 is 12
12 x 6 is 72
The answer is 72
Answer:
1.070MKCl
Explanation:
So we know that the original formula is M= n/L (n being moles of solute, L being liters of solvent)
Since we do not have liters in this problem, we would need to convert milliliters to liters
<u>213 mL= 0.213 L</u>
We then see that we do not have moles, but we do have a mass, being <u>17.0 g.</u> we would need to convert these grams to moles, giving us <u>0.228 mol.</u>
Then, you would plug in <u>0.228 for your n</u>, and now you are ready to solve your original formula, plugging everything in.
M=n/L
M=0.228 mol/0.213L
M= 1.070MKCl
I know this was long, but I hope this helps (:
Answer:
2.5 g mass of Ra-226 will remain after 4800 years.
Explanation:
Given data:
Mass of Ra-226 = 20 g
Sample remain after 4800 years = ?
Solution:
Half life of Ra-226 = 1600 years
Number of half lives passed = T elapsed / half life
Number of half lives passed = 4800 year / 1600 year
Number of half lives passed = 3
At time zero = 20 g
At first half life = 20 g/2 = 10 g
At 2nd half life = 10 g/2 = 5 g
At 3rd half life = 5 g/2 = 2.5 g
Thus, 2.5 g mass of Ra-226 will remain after 4800 years.
