Answer:
0.56
Explanation:
From the formula;
0.693/t1/2 = 2.303/t log (Ao/At)
t1/2 = half life of the C-14 = 5730 y
t = time elapsed = 4800 y
At = Activity of C-14 at time t
Ao= Activity of a living C-14 sample
0.693/5730 = 2.303/4800 log (Ao/At)
1.2 * 10^-4 = 4.8 * 10^-4 log (Ao/At)
log (Ao/At) = 1.2 * 10^-4/4.8 * 10^-4
log (Ao/At) = 0.25
Ao/At = Antilog (0.25)
Ao/At = 1.778
Hence;
At/Ao = (1.778)^-1
At/Ao = 0.56
So what we know:
-Atomic Mass = Protons + Neutrons
-Atomic Number is the number of protons
Magnesium's atomic number is 12, so the natural occurring isotope for magnesium is Mg-12 (12 protons and 12 neutrons). Added up we have an atomic mass of 24 amu. Which means if we added one neutron in Mg-13, our atomic mass would be 25 amu.
We can use the equation:
(amu of isotope 1)x + (amu of isotop 2)(x-1) = Average atomic mass
where isotope 1 is the fractional abundance we're solving for.
Plugged in it looks like this:
24x + 25(1-x) = 24.3
Now to solve for x:
24x + 25 - 25x = 24.3
-x + 25 = 24.3
-x = -.7
x = .7
So in this case, the fractional abundance of Mg-12 would be .7, or 70%.<span />
Vapor pressure is a criteria for a substance's volatility. This is the ability of a substance to transition from liquid to vapor. When the vapor pressure equals the external pressure, liquid turns to gas. Hence, if the substance has higher vapor pressure, then it is volatile. <em>Therefore, Sample A is more volatile than Sample B.</em>
Answer:
0.244 M.
Explanation:
From the question given above, the following data were obtained:
Molarity of stock solution (M₁) = 1 M
Volume of stock solution (V₁) = 0.305 L
Volume of diluted solution (V₂) = 1.25 L
Molarity of diluted solution (M₂) =?
The molarity of the diluted solution can be obtained by using the dilution formula as illustrated below:
M₁V₁ = M₂V₂
1 × 0.305 = M₂ × 1.25
0.305 = M₂ × 1.25
Divide both side by 1.25
M₂ = 0.305 / 1.25
M₂ = 0.244 M
Thus, the molarity of the diluted solution is 0.244 M
