Answer:
Explanation:
Hello there!
In this case, when considering weak acids which have an associated percent dissociation, we first need to set up the ionization reaction and the equilibrium expression:
![HA\rightleftharpoons H^++A^-\\\\Ka=\frac{[H^+][A^-]}{[HA]}](https://tex.z-dn.net/?f=HA%5Crightleftharpoons%20H%5E%2B%2BA%5E-%5C%5C%5C%5CKa%3D%5Cfrac%7B%5BH%5E%2B%5D%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
Now, by introducing x as the reaction extent which also represents the concentration of both H+ and A-, we have:
![Ka=\frac{x^2}{[HA]_0-x} =10^{-4.74}=1.82x10^{-5}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7Bx%5E2%7D%7B%5BHA%5D_0-x%7D%20%3D10%5E%7B-4.74%7D%3D1.82x10%5E%7B-5%7D)
Thus, it is possible to find x given the pH as shown below:
So that we can calculate the initial concentration of the acid:
![\frac{(1.82x10^{-5})^2}{[HA]_0-1.82x10^{-5}} =1.82x10^{-5}\\\\\frac{1.82x10^{-5}}{[HA]_0-1.82x10^{-5}} =1\\\\](https://tex.z-dn.net/?f=%5Cfrac%7B%281.82x10%5E%7B-5%7D%29%5E2%7D%7B%5BHA%5D_0-1.82x10%5E%7B-5%7D%7D%20%3D1.82x10%5E%7B-5%7D%5C%5C%5C%5C%5Cfrac%7B1.82x10%5E%7B-5%7D%7D%7B%5BHA%5D_0-1.82x10%5E%7B-5%7D%7D%20%3D1%5C%5C%5C%5C)
![[HA]_0=3.64x10^{-5}M](https://tex.z-dn.net/?f=%5BHA%5D_0%3D3.64x10%5E%7B-5%7DM)
Therefore, the percent dissociation turns out to be:
![\% diss=\frac{x}{[HA]_0}*100\% \\\\\% diss=\frac{1.82x10^{-5}M}{3.64x10^{-5}M}*100\% \\\\\% diss = 50\%](https://tex.z-dn.net/?f=%5C%25%20diss%3D%5Cfrac%7Bx%7D%7B%5BHA%5D_0%7D%2A100%5C%25%20%5C%5C%5C%5C%5C%25%20diss%3D%5Cfrac%7B1.82x10%5E%7B-5%7DM%7D%7B3.64x10%5E%7B-5%7DM%7D%2A100%5C%25%20%5C%5C%5C%5C%5C%25%20diss%20%3D%2050%5C%25)
Best regards!
The formula units in the substances are as follows:
- Br2 = 8.99 × 10^23 formula units
- MgCl2 = 1.51 × 10^24 formula units
- H2O = 2.57 × 10^24 formula units
- Fe = 2.57 × 10^24 formula units
<h3>How many moles are in 239.2 g of the given substances?</h3>
The moles of the substances are determined from their molar mass.
Molar mass of the substances is given as follows:
- Br2 = 160 g/mol
- MgCl2 = 95 g/mol
- H2O = 18 g/mol
- Fe = 56 g/mol
Formula units = mass/molar mass × 6.02 × 10^23
The formula units in the substances are as follows:
- Br2 = 239.2/160 × 6.02 × 10^23 = 8.99 × 10^23 formula units
- MgCl2 = 239.2/95 × 6.02 × 10^23 = 1.51 × 10^24 formula units
- H2O = 239.2/18 × 6.02 × 10^23 = 2.57 × 10^24 formula units
- Fe = 239.2/56 × 6.02 × 10^23 = 2.57 × 10^24 formula units
In conclusion, the number of formula units is derived from the moles and Avogadro number.
Learn more about formula units at: brainly.com/question/24529075
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<h3>Answer:</h3>
162.43 g of FeCl₂
<h3>
Explanation:</h3>
Step 1: Calculate mass of Fe;
As,
Density = Mass ÷ Volume
Or,
Mass = Density × Volume
Where Volume is the volume of water displaced = 10.4 mL
Putting values,
Mass = 7.86 g.mL⁻¹ × 10.4 mL
Mass = 81.744 g of Fe
Step 2: Calculate amount of FeCl₂;
The balance chemical equation is as follow,
Fe + 2 HCl → FeCl₂ + H₂ ↑
According to this equation,
55.85 g (1 mol) Fe produced = 110.98 g (1 mol) of FeCl₂
So,
81.744 g Fe will produce = X g of FeCl₂
Solving for X,
X = (81.744 g × 110.98 g) ÷ 55.85 g
X = 162.43 g of FeCl₂
The net cell reaction is: 2Al(s) + 2Br2(l) → 4Br(s) + 2Al2O3(s)
What is a net cell reaction?
A net cell reaction is the overall chemical reaction that occurs during a redox reaction in a cell. It is the sum of all of the individual chemical reactions that take place in the cell and is usually written as an equation with the reactants on the left-hand side and the products on the right-hand side.
What is a chemical reaction?
A chemical reaction is a process in which two or more substances interact to form new substances with different chemical properties. Chemical reactions involve the breaking and forming of chemical bonds, releasing or absorbing energy, and can be either exothermic (releasing energy) or endothermic (absorbing energy).
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Answer:
Germanium and Polonium
Explanation:
Can you please mark me brainliest since I was the first person to answer :p
