In the early 1900s, a scientist named Alfred Wegener noticed how the continents seem to fit together and developed the Theory of Continental Drift. Continental drift is the theory that continents can drift apart from one other and have done so in the past. Wegner's theory also explained why fossils of the same plant and animal species are found on both sides of the Atlantic Ocean. In addition similar types of rock and evidence of the same ancient climatic conditions are found on several continents.
Wegner hypothesized that all the separate continents of today were once joined in a single landmass that he called Pangaea.
Answer:
11.39
Explanation:
Given that:
Given that:
Mass = 1.805 g
Molar mass = 82.0343 g/mol
The formula for the calculation of moles is shown below:
Thus,
Given Volume = 55 mL = 0.055 L ( 1 mL = 0.001 L)
Concentration = 0.4 M
Consider the ICE take for the dissociation of the base as:
B + H₂O ⇄ BH⁺ + OH⁻
At t=0 0.4 - -
At t =equilibrium (0.4-x) x x
The expression for dissociation constant is:
![K_{b}=\frac {\left [ BH^{+} \right ]\left [ {OH}^- \right ]}{[B]}](https://tex.z-dn.net/?f=K_%7Bb%7D%3D%5Cfrac%20%7B%5Cleft%20%5B%20BH%5E%7B%2B%7D%20%5Cright%20%5D%5Cleft%20%5B%20%7BOH%7D%5E-%20%5Cright%20%5D%7D%7B%5BB%5D%7D)
x is very small, so (0.4 - x) ≅ 0.4
Solving for x, we get:
x = 2.4606×10⁻³ M
pOH = -log[OH⁻] = -log(2.4606×10⁻³) = 2.61
<u>pH = 14 - pOH = 14 - 2.61 = 11.39</u>
The formula we use would be the graham's law. We do as follows:
<span>E_Kr / E_Ne = sqrt ( M_Ne / M_Kr)
</span>
<span>= sqrt ( 20.1797 g/mol / 83.798 g/mol ) </span>
<span>= sqrt (0.24081) </span>
<span>= 0.4907
</span>
Hope this answers the question. Have a nice day.
Answer:
The molar concentration of HCl in the aqueous solution is 0.0131 mol/dm3
Explanation:
To get the molar concentration of a solution we will use the formula:
<em>Molar concentration = mass of HCl/ molar mass of HCl</em>
<em></em>
Mass of HCl in the aqueous solution will be 40% of the total mass of the solution.
We can extract the mass of the solution from its density which is 1.2g/mL
We will further perform our analysis by considering only 1 ml of this aqueous solution.
The mass of the substance present in this solution is 1.2g.
<em>The mass of HCl Present is 40% of 1.2 = 0.48 g.</em>
The molar mass of HCl can be obtained from standard tables or by adding the masses of Hydrogen (1 g) and Chlorine (35.46 g) = 36.46g/mol
Therefore, the molar concentration of HCl in the aqueous solution is 0.48/36.46 = 0.0131 mol/dm3
