Surface Chemistry Test

Result

Surface Chemistry Test - 26

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Which letter corresponds to the activation energy in this reaction without the addition of a catalyst?

A
A

B
B

C
C

D
D

E
E

Solution

The letter A corresponds to the activation energy in this reaction without the addition of a catalyst. Activation energy is the minimum amount of energy that the reactants must posses to complete the reaction. For uncatalyzed reaction, it is maximum.
Question 2
1 / -0

What is a sol?

A
A solid dispersed in a liquid

B
A liquid dispersed in a gas

C
A gas dispersed in a liquid

D
A gas dispersed in a solid

Solution

Hint: Sol is a gel-like substance.
Correct Answer: Option A

Explanation:

Sol is a colloidal suspension when a solid is dispersed in a liquid.

An example of sol is a gel, blood, paint, etc.

A liquid is dispersed in a gas called aerosols.

A gas dispersed in liquid or solid called foam.

Final Answer: Sol is formed when solid is dispersed in the liquid.
Question 3
1 / -0

The process of enzyme catalysis of biological processes follows a simple pathway and involves three principal species.
The substrate, which we will represent as S, is the molecule that is to undergo reaction. The enzyme, E, acts as the catalyst, and the product, P, is the result of the reaction.
The substrate, S, attaches to a receptor site on the enzyme, E, where it is held in place as the reaction proceeds. Once reaction is completer, the product, P, is released from the receptor site, along with any remaining portion of the substrate molecule.
The process can be represented as shown below, where S-E represents the substrate, bound to the catalyst. As the product forms, the receptor site on the catalyst is again freed to accept another substrate molecule.
$$S + E \rightarrow [S - E]\rightarrow P + E$$
The reaction rate can be investigated either in terms of decreasing concentration of substrate, or increasing appearance of product.
As part of her senior-year STEM project, Athena designs an experiment to study a particular enzyme-catalyzed reaction. Since the product of the reaction is a colored species, she sets up a colorimetric interface to measure the rate of appearance of the colored product, in units of concentration of product over time: $$\dfrac {mol.L^{-1}}{min}$$, or simply, $$\dfrac {M}{min}$$. The plot of product formation vs time appears below.
By design, Athena's experiment began with a large excess of the substrate, S, relative to the enzyme, E.
Which of the following offers the BEST description of the results of her study?

A
After initially increasing rapidly, the rate of product formation slows as the system approaches and achieves equilibrium, as shown by the leveling of the graph. The steady level of product formation indicates the equilibrium state, and can be expected to remain at that level indefinitely, barring a change in temperature.

B
Product formation rises rapidly up to the point at which not enough substrate molecules are available to bond to the enzyme's receptor sites. The rate of product formation levels as enzyme molecules await collision with substrate molecules. This level will begin to slowly diminish over time.

C
The reaction proceeds relatively rapidly until the point where the concentrations of enzyme and substrate level out. From there on, reaction rate is steady, and will remain so, so long as both substrate and enzyme remain in the system.

D
The reaction starts off slowly, as substrate and enzyme molecules collide and bind together. The rate of product formation increases as more and more of the receptor sites on the enzyme become occupied and reaction rate picks up.

Once all the enzyme receptor sites have been occupied, the reaction rate stabilizes, since a particular receptor site only becomes available as the previous reaction at that side goes to completion. Over time, as more and more of the substrate is converted to product, the rate of formation can be expected to decrease.
Question 4
1 / -0

Increased with the addition of a catalyst :

A
Standard voltaic potential

B
Entropy

C
Enthalpy

D
Reaction rate

E
Gibbs free energy

Solution

A catalyst is a substance which speeds up a reaction but is chemically unchanged at the end of the reaction. When the reaction has finished, you would have exactly the same mass of catalyst as you had at the beginning
Question 5
1 / -0

Catalyst used in Rosenmund reaction is:

A
$$Sn$$

B
$$Zn/HCl$$

C
$$Pd/BaSO_4$$

D
$$Ni$$

Solution

A catalyst used in Rosenmund reaction can be prepared by reduction of $$palladium(II) \space chloride$$ solution in the presence of $$BaSO_4$$

The Palladium Catalyst used in Rosenmund’s reduction must be poisoned with $$BaSO_4$$ because the untreated catalyst $$Palladium (Pd)$$ is too reactive and will undergo over reduction forming other products.
Question 6
1 / -0

Which letter corresponds to the total change in energy for the overall reaction?

A
A

B
B

C
C

D
D

E
E

Solution

D is the correct answer. Since the energy required for the overall reaction is the difference between the energy of the products and the energy of the reactants. Here it is represented by D.
Question 7
1 / -0

To which of the following category does ice-cream belong?

A
Solution

B
Emulsion

C
Element

D
Suspension
Solution
An emulsion is a colloid of two or more immiscible liquids where one liquid contains a dispersion of the other liquids. In other words, an emulsion is a special type of mixture made by combining two liquids that normally don't mix.
- Oil and water mixtures are emulsions when shaken together. The oil will form drops and disperse throughout the water.
- Ice-cream is an emulsion of fat globules in a sugar-water solution.
Question 8
1 / -0

The process of separating of cream from milk is called :

A
Emulsification

B
Demulsification

C
Emulsions

D
Electro-osmosis

Solution

The process of separation of two liquids of an emulsion into separate layers is known as demulsification. It can be brought about by heating, centrifuging etc. For example, cream is separated from milk by centrifuging.
Question 9
1 / -0

Soft soaps are:

A
sodium salts of fatty acids

B
potassium salts of fatty acids, containing excess of free alkali

C
potassium salts of fatty acids, containing no free alkali

D
calcium salts of fatty acids

Solution

Potassium salts of fatty acids, containing no free alkali, are called soft soaps.
Question 10
1 / -0

Which one of the following systems has the smallest sized domains in its dispersed phase?

A
Nanoemulsion

B
Coarse suspension

C
Coarse emulsion

D
Microemulsion

Solution

The average diameter of droplets in macro-emulsion is close to one millimeter (i.e., 10⁻³ m). Therefore, since micro- means 10⁻⁶
and emulsion implies that droplets of the dispersed phase have diameters close to 10⁻³ m,
the micro-emulsion denotes a system with the size range of the dispersed phase in the
10⁻⁶ × 10⁻³ m = 10⁻⁹ m range.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Surface Chemistry Test - 26

Result

Surface Chemistry Test - 26

Score

-

Rank

-

SHARING IS CARING

Question 1

A

B

C

D

E

Solution

Question 2

A solid dispersed in a liquid

A liquid dispersed in a gas

A gas dispersed in a liquid

A gas dispersed in a solid

Solution

Question 3

Product formation rises rapidly up to the point at which not enough substrate molecules are available to bond to the enzyme's receptor sites. The rate of product formation levels as enzyme molecules await collision with substrate molecules. This level will begin to slowly diminish over time.

The reaction proceeds relatively rapidly until the point where the concentrations of enzyme and substrate level out. From there on, reaction rate is steady, and will remain so, so long as both substrate and enzyme remain in the system.

Question 4

Standard voltaic potential

Entropy

Enthalpy

Reaction rate

Gibbs free energy

Solution

Question 5

$$Sn$$

$$Zn/HCl$$

$$Pd/BaSO_4$$

$$Ni$$

Solution

Question 6

A

B

C

D

E

Solution

Question 7

Solution

Emulsion

Element

Suspension

Solution

Question 8

Emulsification

Demulsification

Emulsions

Electro-osmosis

Solution

Question 9

sodium salts of fatty acids

potassium salts of fatty acids, containing excess of free alkali

potassium salts of fatty acids, containing no free alkali

calcium salts of fatty acids

Solution

Question 10

Nanoemulsion

Coarse suspension

Coarse emulsion

Microemulsion

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.