Answer:
Kc = 3.72 × 10⁶
Explanation:
Let's consider the following reaction:
NH₄HS(g) ⇄ NH₃(g) + H₂S(g)
At equilibrium, we have the following concentrations:
[NH₄HS] = 0.196 M (assuming a 1 L flask)
[NH₃] = 9.56 × 10² M
[H₂S] = 7.62 × 10² M
We can replace this data in the Kc expression.
![Kc=\frac{[NH_{3}] \times [H_{2}S] }{[NH_{4}HS]} =\frac{9.56 \times 10^{2} \times 7.62 \times 10^{2}}{0.196} =3.72 \times 10^{6}](https://tex.z-dn.net/?f=Kc%3D%5Cfrac%7B%5BNH_%7B3%7D%5D%20%5Ctimes%20%5BH_%7B2%7DS%5D%20%7D%7B%5BNH_%7B4%7DHS%5D%7D%20%3D%5Cfrac%7B9.56%20%5Ctimes%2010%5E%7B2%7D%20%20%5Ctimes%207.62%20%20%5Ctimes%2010%5E%7B2%7D%7D%7B0.196%7D%20%3D3.72%20%5Ctimes%2010%5E%7B6%7D)
Answer is: mass <span>of 4,30 moles of sodium</span> is 98800 mg.
n(Na) = 4,30 mol.
m(Na) = ?
m(Na) = n(Na) · M(Na).
m(Na) = 4,30 mol · 23 g/mol.
m(Na) = 98,90 g.
m(Na) = 98,90 g · 1000 mg/1g.
m(Na) = 98900 mg.
n - amount of substance.
m - mass of substance.
M - molar mass of substance.
Answer:
The correct answer is: Ka= 5.0 x 10⁻⁶
Explanation:
The ionization of a weak monoprotic acid HA is given by the following equilibrium: HA ⇄ H⁺ + A⁻. At the beginning (t= 0) we have 0.200 M of HA. Then, a certain amount (x) is dissociated into H⁺ and A⁻, as is detailed in the following table:
HA ⇄ H⁺ + A⁻
t= 0 0.200 M 0 0
t -x x x
t= eq 0.200M -x x x
At equilibrium, we have the following ionization constant expression (Ka):
Ka= ![\frac{ [H^{+}] [A^{-} ]}{ [HA]}](https://tex.z-dn.net/?f=%5Cfrac%7B%20%5BH%5E%7B%2B%7D%5D%20%20%5BA%5E%7B-%7D%20%5D%7D%7B%20%5BHA%5D%7D)
Ka= 
Ka= 
From the definition of pH, we know that:
pH= - log [H⁺]
In this case, [H⁺]= x, so:
pH= -log x
3.0= -log x
⇒x = 10⁻³
We introduce the value of x (10⁻³) in the previous expression and then we can calculate the ionization constant Ka as follows:
Ka= 
= 
= 5.025 x 10⁻⁶= 5.0 x 10⁻⁶
Expansion
Explanation:
Expansion is the change is size of a body with increasing temperature and tension.
Bridges are built of iron. Iron thermally expands in the presence of increased temperature during the day. The length of the iron will increase by simple fractions. At night, when temperature drops, the bar returns back to its initial position.
- The allowance for expansion of the metal is made in order to prevent tension within the structure.
- Not doing this will cause the material to break since there is no free space for the bar to change shape.
Learn more:
Expansion in gases brainly.com/question/9979757
#learnwithBrainly
Hello!
The mass number in isotope notation is denoted A, the atomic number is denoted as Z, and the element is denoted as X.
In the given isotope, the mass of the isotope is 212 amu, and the atomic number is 82.
We know that the number of electrons, and protons are equal to the atomic number. Therefore, there are 82 protons. Also, to find the number of neutrons, we subtract the atomic number from the atomic mass.
212 - 82 = 130 neutrons
<u>Final answers</u>:
- Atomic Number: 82
- Mass number: 212
- Number of Protons: 82
- Number of Neutrons: 130
