Answer:
Explanation:
Let A₀ = the original amount of ⁵⁵Co
.
The amount remaining after one half-life is ½A₀.
After two half-lives, the amount remaining is ½ ×½A₀ = (½)²A₀.
After three half-lives, the amount remaining is ½ ×(½)²A₀ = (½)³A₀.
The general formula for the amount remaining is:
A =A₀(½)ⁿ
where n is the number of half-lives
n = t/t_½
Data:
A = 1.90 ng
t = 45 h
t_½ = 18.0 h
Calculation:
(a) Calculate n
n = 45/18.0 = 2.5
(b) Calculate A
1.90 = A₀ × (½)^2.5
1.90 = A₀ × 0.178
A₀ = 1.90/0.178 = 10.7 ng
The original mass of ⁵⁵Co was .
Answer:
0.0025g/cm³
Explanation:
Given parameters:
Mass of the brown sugar = 12.9g
dimension of the sugar = 8cm
unknown:
density of the sugar = ?
Solution
Density is defined as the mass per unit volume of a substance. The expression is given below:
Density = 
We know the mass of the substance but the volume is unknown:
Volume of the brown sugar = l x bx h = 8x8x8 = 512cm³
Density of the brown sugar = 
= 0.0025g/cm³
I do not believe you're asking this...
OK. Sulfur has a total of 24 isotopes. Every isotope has 16 protons and the number of neutrons ranges from 10 to 33 inclusive.
Phosphorus has a total of 23 isotopes. They have 15 protons, and between 9 and 31 neutrons inclusive. So here we go.
S-49
S-48
S-47, P-46
S-46, P-45
S-45, P-44
S-44, P-43
S-43, P-42
S-42, P-41
S-41, P-40
S-40, P-39
S-39, P-38
S-38, P-37
S-37, P-36
S-36, P-35
S-35, P-34
S-34, P-33
S-33, P-32
S-32, P-31
S-31, P-30
S-30, P-29
S-29, P-28
S-28, P-27
S-27, P-26
S-26, P-25
P-24
If you're looking for STABLE isotopes, then the list is much smaller.
S-36
S-34
S-33
S-32, P-31
