Answer:
I believe the answer is a
Explanation:
Painting does not save the chemical structure for preserving metals.
If this helped can i please have brainliest?
When the titration of HCN with NaOH is:
HCN (aq) + OH- (aq) → CN-(aq) + H2O(l)
So we can see that the molar ratio between HCN: OH-: CN- is 1:1 :1
we need to get number of mmol of HCN = molarity * volume
= 0.2 mmol / mL* 10 mL = 2 mmol
so the number of mmol of NaOH = 2 mmol according to the molar ratio
so, the volume of NaOH = moles/molarity
= 2 mmol / 0.0998mL
= 20 mL
and according to the molar ratio so, moles of CN- = 2 mmol
∴the molarity of CN- = moles / total volume
= 2 mmol / (10mL + 20mL ) = 0.0662 M
when we have the value of PKa = 9.31 and we need to get Pkb
so, Pkb= 14 - Pka
= 14 - 9.31 = 4.69
when Pkb = -㏒Kb
4.69 = -㏒ Kb
∴ Kb = 2 x 10^-5
and when the dissociation reaction of CN- is:
CN-(aq) + H2O(l) ↔ HCN(aq) + OH- (aq)
by using the ICE table:
∴ the initials concentration are:
[CN-] = 0.0662 M
and [HCN] = [OH]- = 0 M
and the equilibrium concentrations are:
[CN-] = (0.0662- X)
[HCN] = [OH-]= X
when Kb expression = [HCN][OH-] /[CN-]
by substitution:
2 x 10^-5 = X^2 / (0.0662 - X)
X = 0.00114
∴[OH-] = X = 0.00114
when POH = -㏒[OH]
= -㏒ 0.00114
POH = 2.94
∴PH = 14 - 2.94 = 11.06
Answer:
6.37 L
Explanation:
- Used combined gas law. Get rid of temperature since it is constant. (You could also keep it and get the same answer, but it is another step)
- Change C to K
- Change torr to atm
- Hope this helps! I would be glad to give you a step by step explanation. Please let me know if you want help on how to do these types of problems.
<span>Kc = [H2S]²*[O2]³ / [H2O]²*[SO2]²
Let x be the moles of H2S formed. Each mole of H2S takes one each mole of H2O and SO2 so after the reactions
[H2O] = 2.8 - x and [SO2] = 2.6 - x also for each mole of H2S, 1.5 moles of O2 are formed, so [O2] = 1.5*x
Kc = x²*(1.5*x)³ / (2.8 - x)²*(2.6 - x)²
Thus use 2.8 - x = 2.8 and 2.6 - x = 2.6 in the above equation for Kc:
Kc = x²*(1.5*x)³ / 2.8²*2.6² = 3.375x^5 / 2.8²*2.6² = 0.06368*x^5
x^5 = 1.3*10^-6 / 0.06368 = 2.0414*10^-5
x = 0.115M </span>
hope it helps
Answer:
An atom
Explanation:
Matter is composed of atoms and atom is further consist of smaller particles called electron, proton and neutrons.
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10-31 Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
The atom interact with another atom by sharing or transferring the electrons. The properties of substances are depend upon the electrons present out side the nucleus.
