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
Igoryamba
3 years ago
15

Calculate the pH at the equivalence point when 10.0 mL of 0.10 M HC9H7O2 (Ka = 3.6 × 10–5) is titrated against 0.20 M sodium hyd

roxide
8.63
5.37
2.72
4.44
Chemistry
1 answer:
gtnhenbr [62]3 years ago
8 0

<u>Given:</u>

Volume of HC9H7O2 = 10.0 ml = 0.010 L

Molarity of HC9H7O2 = 0.10 M

Ka (HC9H7O2) = 3.6 * 10-5

Molarity of NaOH = 0.20

<u>To determine:</u>

pH at the equivalence point

<u>Explanation:</u>

The titration equation is:

C9H7OOH + NaOH ↔ C9H7OONa + H2O

As per the reaction stoichiometry-

1 mole of the weak acid reacts with 1 mole of base to form 1 mole of the conjugate base

# Moles of C9H7COOH = M * V = 0.10 M * 0.010 L = 0.001 moles

Now, based on the stoichiometry:

# moles of C9H7COOH = # moles of NaOH = # moles of C9H7COONa =  0.001 moles

volume of NaOH required to reach the eq. pt is:

V(NaOH) = Moles NaOH/Molarity NaOH

              = 0.001 moles/0.20 M = 0.005 L = 5ml

Total volume = 10.0 ml + 5.0 ml = 15 ml

The concentration of the conjugate base the equivalence point is:

[C9H7COONa] = 0.001/0.015 = 0.0667 M

To find pH set up the ICE table as follows:              

              C9H7COO- + H2O ↔ C9H7COOH + OH-

I               0.0667                           0                      0

C              -x                                     +x                   +x

E            0.0667-x                          +x                    +x

Kb = [C9H7COOH][OH-]/[C9H7COO-]

Kw/Ka = x²/(0.0667-x)

10⁻¹⁴/3,6*10⁻⁵ = x²/(0.0667-x)

x = [OH-] = 4.30*10⁻⁶ M

p[OH-] = -log[OH-] = -log[4.30*10⁻⁶] = 5.37

pH = 14-p[OH] = 14-5.37 = 8.63

Ans (a)

pH = 8.63


You might be interested in
What is the pressure in a 245 L tank that contains 5.21 kg of helium at 27 Celsius ​
Kitty [74]
<h2><u>Answer:</u></h2>

(These are not rounded to the correct decimal)

130.94 atm

13,266.6 kPa

99,571.4 mmHg

<h2><u>Explanation:</u></h2>

<u></u>

PV = nRT

V = 245L

P = ?

R = 0.08206 (atm) , 8.314 (kPa) , 62.4 (mmHg)

T = 273.15 + 27 = 300.15K

n = 1302.5 moles

How I found (n).

5.21kg x 1000g/1kg x 1 mole/4.0g = 1302.5 moles

Now, plug all the numbers into the equation.

Pressure in atm = (1302.5)(0.08206)(300.15) / 245 = 130.94 atm (not rounded to the correct decimal)

Pressure in kPa = (1302.5)(8.314)(300.15) / 245 = 13,266.6 kPa (not rounded to the correct decimal)

Pressure in mmHg = (1302.5)(62.4)(300.15) / 245 = 99,571.4 mmHg (not rounded to the correct decimal)

5 0
3 years ago
When different elements react, their atoms join with other atoms.
FinnZ [79.3K]

Answer:

compound is formed .............

8 0
2 years ago
Key terms: Reset Stereoisomers that are not mirror images of each are ____________ . The chemical and physical properties of two
sergejj [24]

Answer:

Enantiomers/ Isomers/ Stereoisomers/ Meso compounds/ Constitutional isomers/ Diastereomers.

Explanation:

Isomers are molecules that have the same chemical formula but have different conformation, or in its connections, or the orientation in space. Isomers have different chemical and physical properties (second blank).

The isomers that only differ by the orientation of their atoms in space are called stereoisomers (third blank).

The stereoisomers that have a chiral carbon and do not mirror images of each are called enantiomers (first blank). They can deviate the polarized light.

When a compound has two or more chiral carbons but they compensate for the deviation of the light, and the compound is optically inactive, it's called a meso compound (fourth blank).

When the isomers differ in the way the atoms are connected it's called a constitutional isomer (fifth blank).

When the molecule has more than one chiral carbon, it will have pairs of enantiomers. The isomers that aren't of the same pair are nonsuperimposable mirror images of each other and are called diastereomers (last blank).

6 0
3 years ago
How does the periodic table make it easier for the scientist to work with and study elements
ololo11 [35]

Answer:

The periodic table has gone through many changes since Dmitri Mendeleev drew up its original design in 1869, yet both the first table and the modern periodic table are important for the same reason: The periodic table organizes elements according to similar properties so you can tell the characteristics of an element just by looking at its location on the table

Explanation:

hope it helps you

3 0
3 years ago
Read 2 more answers
#1: Which of the following is an exothermic reaction?
aleksandrvk [35]
<span>An exothermic reaction is one in which heat is released from the reagents into the ambient environment. Perhaps somewhat counterintuitively, condensation is in fact an example of such a reaction. During the process of the gas-to-liquid phase change, water goes from a higher-energy to lower-energy state of matter, and, as such, releases heat into the environment.</span>
5 0
3 years ago
Other questions:
  • Isobutyl propionate is the substance that provides the flavor for rum extract. combustion of a 1.152 g sample of this carbon-hyd
    9·1 answer
  • Why is warm honey easier to pour than cold honey?
    14·2 answers
  • 14 point. Please help need this ASAP.
    6·1 answer
  • Please explain how to do it as well!
    9·2 answers
  • Please help, lots of points!
    8·1 answer
  • Balance the following equation and
    8·1 answer
  • Pls pls help me me pls
    9·1 answer
  • 8. Which of the following elemental gases would have properties closest to an ideal gas?
    14·1 answer
  • 17. this gas combines with iron in rock and turns it into<br> rust
    11·1 answer
  • Classify the following statements as observation, inference, prediction, measuring or classifying
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!