We can calculate years by using the half-life equation. It is expressed as:
A = Ao e^-kt
<span>where A is the amount left at t years, Ao is the initial concentration, and k is a constant.
</span>From the half-life data, we can calculate for k.
1/2(Ao) = Ao e^-k(1620)
<span>k = 4.28 x 10^-4
</span>
0.125 = 1 e^-<span>4.28 x 10^-4 (</span>t)
t = 4259 years
100. g CCl4* (1 mol CCl4/ 153.8 g CCl4)* (6.02*10^23 CCl4 molecules/ 1 mol CCl4)= 3.91*10^23 CCl4 molecules.
(Note that the units cancel out so you get the answer)
Hope this helps~
Answer:
There are
4.517
⋅
10
23
atoms of Zn in 0.750 mols of Zn.
Explanation:
Since we know that there are
6.022
⋅
10
23
atoms in every mole of a substance (Avogadro's Number), there are
6.022
E
23
⋅
0.750
atoms of Zn in 0.750 mols of Zn.
(a) One form of the Clausius-Clapeyron equation is
ln(P₂/P₁) = (ΔHv/R) * (1/T₁ - 1/T₂); where in this case:
Solving for ΔHv:
- ΔHv = R * ln(P₂/P₁) / (1/T₁ - 1/T₂)
- ΔHv = 8.31 J/molK * ln(5.3/1.3) / (1/358.96 - 1/392.46)
(b) <em>Normal boiling point means</em> that P = 1 atm = 101.325 kPa. We use the same formula, using the same values for P₁ and T₁, and replacing P₂ with atmosferic pressure, <u>solving for T₂</u>:
- ln(P₂/P₁) = (ΔHv/R) * (1/T₁ - 1/T₂)
- 1/T₂ = 1/T₁ - [ ln(P₂/P₁) / (ΔHv/R) ]
- 1/T₂ = 1/358.96 K - [ ln(101.325/1.3) / (49111.12/8.31) ]
(c)<em> The enthalpy of vaporization</em> was calculated in part (a), and it does not vary depending on temperature, meaning <u>that at the boiling point the enthalpy of vaporization ΔHv is still 49111.12 J/molK</u>.
<u>Answer</u>:
By tracking oxidation numbers we can identify the number electron in the atom
<u>Explanation</u>:
Tracking of electrons helps us to know when and how many electrons get transferred from one atom to other atom . Oxidation referred as the “loss of one or more electrons” by an atom. When the oxidation number of an element increases, there is a loss of electrons and that element is being oxidized. Oxidation numbers are usually written with the sign (+plus or −minus) followed by the magnitude, which is the opposite of charges on ions. In their elemental stage oxidation number of an atom is zero.
