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
irakobra [83]
3 years ago
13

Consider the titration of 1L of 0.36 M NH3 (Kb=1.8x10−5) with 0.74 M HCl. What is the pH at the equivalence point of the titrati

on? A) 4.69 B) 4.85 C) 4.94 D) 9.06 E) 9.31
Chemistry
1 answer:
worty [1.4K]3 years ago
7 0

Answer:

C

Explanation:

The question asks to calculate the pH at equivalence point of the titration between ammonia and hydrochloric acid

Firstly, we write the equation of reaction between ammonia and hydrochloric acid.

NH3(aq)+HCl(aq)→NH4Cl(aq)

Ionically:

HCl + NH3 ---> NH4  +  Cl-

Firstly, we calculate the number of moles of  the ammonia  as follows:

from c = n/v and thus, n = cv = 0.36 × 1 = 0.36 moles

At the equivalence point, there is equal number of moles of ammonia and HCl.

Hence, volume of HCl = number of moles/molarity of HCl = 0.36/0.74 = 0.486L

Hence, the total volume of solution will be 1 + 0.486 = 1.486L

Now, we calculate the concentration of the ammonium ions = 0.36/1.486 = 0.242M

An ICE TABLE IS USED TO FIND THE CONCENTRATION OF THE HYDROXONIUM ION(H3O+). ICE STANDS FOR INITIAL, CHANGE AND EQUILIBRIUM.

                 NH4+      H2O     ⇄  NH3        H3O+

I                0.242                           0             0

C                 -X                              +x              +X

E             0.242-X                          X              X

Since the question provides us with the base dissociation constant value K b, we can calculate the acid dissociation constant value Ka

To find this, we use the mathematical equation below

K a ⋅ K b    = K w

 

, where  K w- the self-ionization constant of water, equal to  

10 ^-14  at room temperature

This means that you have

K a = K w.K b   = 10 ^− 14 /1.8 * 10^-5 =  5.56 * 10^-10

Ka = [NH3][H3O+]/[NH4+]

= x * x/(0.242-x)

Since the value of Ka is small, we can say that 0.242-x ≈  0.242

Hence, K a = x^2/0.242 = 5.56 * 10^-10

x^2 = 0.242 * 5.56 * 10^-10 = 1.35 * 10^-10

x = 0.00001161895

[H3O+] = 0.00001161895

pH = -log[H3O+]

pH = -log[0.00001161895 ] = 4.94

You might be interested in
When a substance is entering a phase change, the gain or loss of heat is a result of?
sweet [91]

When a substance is entering a phase change, the gain or loss of heat is a result of energy gained or lost in forming or breaking intermolecular interaction.

The constant temperatures occur when a substance is undergoing a phase transition.  If heat is removed from a substance , such as in freezing and condensation , then the process is exothermic . In this instance , heat is decreasing the speed of the molecules causing then move slower.

In chemistry and thermodynamics, phase transitions (or phase changes) are the physical processes of transition between a state of a medium, identified by some parameters, and another one, with different values of the parameters.

Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, as well as plasma in rare cases.

For example, a phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change, often discontinuously, as a result of the change of external conditions, such as temperature, pressure, or others.

For example, a liquid may become gas upon heating to the boiling point, resulting in an abrupt change in volume. The measurement of the external conditions at which the transformation occurs is termed the phase transition. Phase transitions commonly occur in nature and are used today in many technologies.

Learn more about  phase change here :

brainly.com/question/12390797

#SPJ4

8 0
2 years ago
What is the ph of the benzoic acid solution prior to adding sodium benzoate?
Reika [66]
The acid dissociation constant of benzoic acid is 6.5 x 10^-5. Therefore, the pH of the benzoic acid solution prior to adding sodium benzoate is:

pH = -log[Ka]
pH = -log (6.5 x 10^-5)
pH = 4.19

The pH of the benzoic acid solution is 4.19 which is acidic, but a weak acid. 

7 0
3 years ago
List at least three scientific disciplines related to chemistry mentioned or alluded to in the article. The Ozone Hole
SVETLANKA909090 [29]

Answer: biology, climate Science, astronomy etc.

Explanation:

The scientific disciplines that are related to chemistry mentioned or alluded to in the article are:

• Biology: Biology is a natural science which studies living organisms, and this include their molecular interactions, evolution, physical structure, and chemical processes.

• Astronomy: Astronomy is the study of space, and the universe. In astronomy, the stars, planets, and galaxies are all studied.

• Climate science: Climate science is also referred to as climatology and it's the scientific study of climate.

7 0
3 years ago
The Electrical conductivity of an aqueous solution depends on the concentration of which particles in the solution
anyanavicka [17]
It depends on the concentration of ions which are responsible for the electrical conductivity in aqueous solutions.
6 0
2 years ago
Read 2 more answers
If the decomposition of a sample of k c l o 3 kclox3 produces 3. 29 g of o 2 ox2 , what was the mass (g) of the original sample?
____ [38]

The mass (g) of the original sample after decomposition is 8.3983 g.

A decomposition reaction can be described as a chemical reaction wherein one reactant breaks down into or extra merchandise.

explanation:

Reaction          2KClO₃ ⇒ 2KCl + 3O₂

moles               2               2            3

molar mass    122.55        74.55    32

Given, Mass of O₂ = 3.29g ⇒ moles of O₂

                                            =  (3.29/32) = 0.1028

3 moles of O₂  produced by 2 moles of KClO₃

Therefore, 0.1028 moles of O₂  produced by (2*0.1028/3) = 0.06853 moles of Kclo₃

Mass of KClo₃ in original sample is = moles * molar mass

                                                        = 0.06853 * 122.55

                                                       = 8.3983 g

A decomposition response occurs whilst one reactant breaks down into or extra merchandise. this may be represented through the general equation: XY → X+ Y. Examples of decomposition reactions consist of the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.

Learn more about decomposition here:-brainly.com/question/27300160

#SPJ4

5 0
1 year ago
Other questions:
  • Is a solution in which (OH) = 1.0 10-1M acidic, basic, or neutral?
    9·1 answer
  • Magma _____ to form igneous rock.
    5·1 answer
  • A solution of KCIO3 is prepared using 75 grams of the solute in enough water to make 0.250 liters of solution. The gram-formula
    6·1 answer
  • Part i. you considered the equilibrium: fe3+(aq) + scn-(aq) fe(scn)2+(aq), and compared the color of the solutions in four test
    6·1 answer
  • Which statement best describes a solution? a mixture consisting of minute particles suspended in a medium that start moving abou
    7·1 answer
  • A student takes an object with an accepted mass of 120.0 grams and masses it on their
    10·1 answer
  • What is the metric unit that is used to describe weight as a measure of the force of gravity ?
    12·2 answers
  • This kind of bond is formed when an atom with low electronegativity donates electrons to an
    13·1 answer
  • What is a substance combination of different atoms?
    7·2 answers
  • Calculate the wavelength and frequency of an emitted photon of gamma radiation that has energy of 3.02 × 1011 J/mol.
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!