Answer:
4.8 %
Explanation:
We are asked the concentration in % by mass, given the molarity of the solution and its density.
0.8 molar solution means that we have 0.80 moles of acetic acid in 1 liter of solution. If we convert the moles of acetic acid to grams, and the 1 liter solution to grams, since we are given the density of solution, we will have the values necessary to calculate the % by mass:
MW acetic acid = 60.0 g/mol
mass acetic acid (the solute) = 0.80 mol x 60 g / mol = 48.00 g
mass of solution = 1000 cm³ x 1.010 g/ cm³ (1l= 1000 cm³)
= 1010 g
% (by mass) = 48.00 g/ 1010 g x 100 = 4.8 %
When we can get Pka for K2HPO4 =6.86 so we can determine the Ka :
when Pka = - ㏒ Ka
6.86 = -㏒ Ka
∴Ka = 1.38 x 10^-7
by using ICE table:
H2PO4- → H+ + HPO4
initial 0.4 m 0 0
change -X +X +X
Equ (0.4-X) X X
when Ka = [H+][HPO4] / [H2PO4-]
by substitution:
1.38 X 10^-7 = X^2 / (0.4-X) by solving for X
∴X = 2.3x 10^-4
∴[H+] = X = 2.3 x 10^-4
∴PH = -㏒[H+]
= -㏒ (2.3 x 10^-4)
∴PH = 3.6
Answer : The correct answer is option 2 : 0.10 M NaCl and 0.10 M NaClO₄
Explanation :
Solutions are classified into 3 categories.
1) Strong electrolytes : These are the solutions that dissociate completely forming ions . They are good conductors of electricity.
Example : All strong acids, bases and the salts made by strong acid/base are strong electrolytes .
2) Weak electrolytes : These substances do not dissociate completely thereby forming fewer ions. They are weak conductors of electricity.
3) Non electrolytes : These are the substances that do not dissociate at all. They do not form ions in aqueous medium. They are bad conductors of electricity.
Let us take a look at the given options and find out what type of solution do we have .
Option 1 : NH₃ is a weak electrolyte whereas NH₄Cl is a strong electrolyte bcause NH₄Cl is made by combination of NH₃ and HCl ( HCl is a strong acid)
Therefore NH₃ would carry electricity less efficiently than NH₄Cl.
Option 2 : Both NaCl and NaClO₄ are strong electrolytes. Therefore they will conduct electrical current equally well
Option 3 : NaNO₃ is a strong electrolyte but HNO₂ is a weak electrolyte. Therefore they will not carry the current equally
Therefore the correct option is option 2
Answer:
RbOH → Rb⁺ + OH⁻
As the hydroxide can gives the OH⁻ in water, it is considered as an Arrhenius's base
Explanation:
Arrhenius theory states that a compound is considered a base, if the compound can generate OH⁻ ions in aqueous solution.
Our compound is the RbOH.
When it is put in water, i can dissociate like this:
RbOH → Rb⁺ + OH⁻
As the hydroxide can gives the OH⁻ in water, it is considered as an Arrhenius's base
Answer: Cu
Explanation: It is Cu because the origin of the word Copper comes from the latin word "Cuprum".
