1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Tanya [424]
3 years ago
8

A 60.0 mL solution of 0.112 M sulfurous acid (H2SO3) is titrated with 0.112 M NaOH. The pKa values of sulfurous acid are 1.857 (

pKa1) and 7.172 (pKa2).
A) Calculate pH at the first equivalence point.
B) Calculate pH at the second equivalence point.
Chemistry
1 answer:
djverab [1.8K]3 years ago
4 0

Answer:

a)4.51

b) 9.96

Explanation:

Given:

NaOH = 0.112M

H2S03 = 0.112 M

V = 60 ml

H2S03 pKa1= 1.857

pKa2 = 7.172

a) to calculate pH at first equivalence point, we calculate the pH between pKa1 and pKa2 as it is in between.

Therefore, the half points will also be the middle point.

Solving, we have:

pH = (½)* pKa1 + pKa2

pH = (½) * (1.857 + 7.172)

= 4.51

Thus, pH at first equivalence point is 4.51

b) pH at second equivalence point:

We already know there is a presence of SO3-2, and it ionizes to form

SO3-2 + H2O <>HSO3- + OH-

Kb = \frac{[ HSO3-][0H-]}{SO3-2}

Kb = \frac{10^-^1^4}{10^-^7^.^1^7^2} = 1.49*10^-^7

[HSO3-] = x = [OH-]

mmol of SO3-2 = MV

= 0.112 * 60 = 6.72

We need to find the V of NaOh,

V of NaOh = (2 * mmol)/M

= (2 * 6.72)/0.122

= 120ml

For total V in equivalence point, we have:

60ml + 120ml = 180ml

[S03-2] = 6.72/120

= 0.056 M

Substituting for values gotten in the equation Kb=\frac{[HSO3-][OH-]}{[SO3-2]}

We noe have:

1.485*10^-^7=\frac{x*x}{(0.056-x)}

x = [OH-] = 9.11*10^-^5

pOH = -log(OH) = -log(9.11*10^-^5)

=4.04

pH = 14- pOH

= 14 - 4.04

= 9.96

The pH at second equivalence point is 9.96

You might be interested in
Between magnesium and calcium, which has the highest ionization energy, and why?
quester [9]

Answer:

magnesium

Explanation:

magnesium has fewer valence shells meaning that the protons have a stronger hold on the electrons and it would take more energy to remove an electron to create an ion.

3 0
3 years ago
In what month is the sun farthest below or south of the celestial equator?
KIM [24]

Answer: December

Explanation:

The winter solstice is around December 21, marking the date on which the Sun is lowest in the sky at noon and rises and sets farthest south.

7 0
3 years ago
Read 2 more answers
At 400 K oxalic acid decomposes according to the reaction:H2C2O4(g)→CO2(g)+HCOOH(g)In three separate experiments, the intial pre
padilas [110]

Answer:

v = 2,66x10⁻⁵ P[H₂C₂O₄]

Explanation:

For the reaction:

H₂C₂O₄(g) → CO₂(g) + HCOOH(g)

At t = 0, the initial pressure is just of H₂C₂O₄(g). At t= 20000 s, pressures will be:

H₂C₂O₄(g) = P₀ - x

CO₂(g) = x

HCOOH(g) = x

P at t=20000 is:

P₀ - x + x + x = P₀+x. That means P at t=20000s - P₀ = x

For 1st point:

x = 92,8-65,8 = 27

Pressure of H₂C₂O₄(g) at t=20000s: 65,8-27 = 38,8

2nd point:

x = 130-92,1 = 37,9

H₂C₂O₄(g): 92,1 - 37,9 = 54,2

3rd point:

x = 157-111 = 46

H₂C₂O₄(g): 111-46 = 65

Now, as the rate law is :

v = k P[H₂C₂O₄]

Based on integrated rate law, k is:

(- ln P[H₂C₂O₄] + ln P[H₂C₂O₄]₀) / t = k

1st point:

k = 2,64x10⁻⁵

2nd point:

k = 2,65x10⁻⁵

3rd point:

k = 2,68x10⁻⁵

The averrage of this values is:

k = 2,66x10⁻⁵

That means law is:

v = 2,66x10⁻⁵ P[H₂C₂O₄]

I hope it helps!

4 0
3 years ago
Please help with question 4 and 5 please!!
ratelena [41]
Question four is : Gaseous state

Question five is : A rise in temperature increases the kinetic energy and speed of particles; it does not weaken the forces between them. The particles in solids vibrate about fixed positions; even at very low temperatures. Individual particles in liquids and gases have no fixed positions and move chaotically.

Hope this helps!

Have a great day!
8 0
2 years ago
Which nuclide is most likely to be radioactive and synthetic
White raven [17]

Answer:

237/93 np

Explanation:

sub to tkwick

7 0
2 years ago
Other questions:
  • The dimensions of a cuboid shape cupboard are 1.31 m wide by 0.9 m long by 1.70 m tall what is the volume of the cupboard taking
    11·1 answer
  • Which substance would you most likely need to cool to the lowest temperature before it condenses?
    14·2 answers
  • For a single component system, why do the allotropes stable at high temperatures have higher enthalpies than allotropes stable a
    6·1 answer
  • What mass of sodium oxalate na2c2o4 is needed to prepare 0.250 l of a 0.100 m solution?
    15·2 answers
  • Which learning theory is based on associative learning?
    8·1 answer
  • Water (10 kg/s) at 1 bar pressure and 50 C is pumped isothermally to 10 bar. What is the pump work? (Use the steam tables.) -7.3
    10·1 answer
  • Two elements in the second transition series (Y through
    9·2 answers
  • Which characteristic influences the polarity of these molecules?
    8·1 answer
  • This graph represents a population of molecules in a gas versus the distribution of the average velocity(speed) of its molecules
    6·1 answer
  • According to the Kinetic Molecular Theory, all substances contain entities that are in a continuous random motion.Could you plea
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!