Answer:
The solution becomes colorless and a light blue precipitate is formed.
Explanation:
When sodium hydroxide is added to copper(II) nitrate solution, a precipitate of copper(II) hydroxide is formed.
The solution gradually becomes colorless as the light blue precipitate appears.
The reaction is complete (enough sodium hydroxide has been added) when the blue color of the solution completely disappears.
The equation of the reaction is;
Cu(NO3)2(aq) + 2NaOH(aq) → Cu(OH)2(s) + 2NaNO3(aq)
Answer:
Sulfur is an element is Period 3 with 6 valence electrons.
<span>Answer: The 1 kg of water will reach the lowest temperature
</span>
Both of the objects is water so their specific heat should be same. The heat removed from the 2kg of water which is 2 times of mass than the 1kg water. Since the heat removed, both of their temperatures will drops. But 2kg water temperature drops will be half of 1kg water.
Answer : The value of acid dissociation constant is, 
Solution : Given,
Concentration pyridinecarboxylic acid = 0.78 M
pH = 2.53
First we have to calculate the hydrogen ion concentration.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
![2.53=-\log [H^+]](https://tex.z-dn.net/?f=2.53%3D-%5Clog%20%5BH%5E%2B%5D)
![[H^+]=2.95\times 106{-3}M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D2.95%5Ctimes%20106%7B-3%7DM)
Now we have to calculate the acid dissociation constant.
The equilibrium reaction for dissociation of (weak acid) is,

initially conc. 0.78 0 0
At eqm. (0.78-x) x x
The expression of acid dissociation constant for acid is:
![k_a=\frac{[C_6H_4NO_2^-][H^+]}{[C_6H_4NO_2]}](https://tex.z-dn.net/?f=k_a%3D%5Cfrac%7B%5BC_6H_4NO_2%5E-%5D%5BH%5E%2B%5D%7D%7B%5BC_6H_4NO_2%5D%7D)
As, ![[H^+]=[C_6H_4NO_2^-]=x](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BC_6H_4NO_2%5E-%5D%3Dx)
So, 
Now put all the given values in this formula ,we get:



Therefore, the value of acid dissociation constant is, 
Answer:
0.1357 M
Explanation:
(a) The balanced reaction is shown below as:

(b) Moles of
can be calculated as:
Or,
Given :
For
:
Molarity = 0.1450 M
Volume = 10.00 mL
The conversion of mL to L is shown below:
1 mL = 10⁻³ L
Thus, volume = 10×10⁻³ L
Thus, moles of
:
Moles of
= 0.00145 moles
From the reaction,
1 mole of
react with 2 moles of NaOH
0.00145 mole of
react with 2*0.00145 mole of NaOH
Moles of NaOH = 0.0029 moles
Volume = 21.37 mL = 21.37×10⁻³ L
Molarity = Moles / Volume = 0.0029 / 21.37×10⁻³ M = 0.1357 M