Tag: chemistry

Questions Related to chemistry

Which of the following generalizations cannot be made about the phase change of a pure substance from solid to liquid?

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. It involves a change in potential energy.

  2. It involves no change in temperature.

  3. It involves a change in kinetic energy.

  4. It involves a change in entropy.

Show answer
Correct Option: C
Explanation:

When a pure substance undergoes a phase change from solid to liquid state,there will increases in temperature so,the collision rate do not increases which implies that there is no change in kinetic energy,the entire heat involves a change in potential energy.It involves change in entropy because more free particles are generated from solid to liquid.

$\displaystyle Gas\rightarrow Solid$ 


The process is known as :

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. sublimation

  2. condensation

  3. evaporation

  4. deposition

  5. melting

Show answer
Correct Option: D
Explanation:

Deposition is a phase transition in which gas transforms into solid without passing through the liquid phase.


Hence the correct option is D.

Statement I: Water droplets form on the outside of a beaker containing an ice bath.
Statement II: Water vapor molecules in the air lose energy when they collide with the cold glass surface and condense.

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I.

  2. Both Statement I and Statement II are correct, but Statement II is not the correct explanation of Statement I. 

  3. Statement I is correct, but Statement II is incorrect.

  4. Statement I is incorrect, but Statement II is correct.

Show answer
Correct Option: A
Explanation:

Condensation is a process in which gaseous molecules lose energy and gets converted to liquid state.

Water droplets are formed on outside of a beaker containing ice bath because water molecules in air loose energy when they collide with the cold glass surface  and condense.

An electron having mass '$m$' and kinetic energy $E$ enter in the uniform magnetic field $B$ perpendicularly, then its frequency will be:

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. $\displaystyle \dfrac{eE}{qVB}$

  2. $\displaystyle \dfrac{2\pi m}{eB}$

  3. $\displaystyle \dfrac{eB}{2\pi m}$

  4. $\displaystyle \dfrac{2m}{eBE}$

Show answer
Correct Option: C
Explanation:

It velocity of particle is perpendicular to the magnetic field,the particles moves in a circle.The centripetal force is experienced by electron is $qVB$

$\cfrac { { m }v^{ 2 } }{ r } =qVB\ \cfrac { mv }{ r } =qB\ $
$mw=qB$
$w=qB/m$
$f=\cfrac { qB }{ 2\pi m } $
Frequency$=\cfrac { eB }{ 2\pi m } $

A proton is about 1840 times heavier than an electron. When it is accelerated by a potential difference of 1 kV, its kinetic energy will be :

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. 1840 keV

  2. 1/1840 keV

  3. 1 keV

  4. 920 keV

Show answer
Correct Option: C
Explanation:
We know that :

Kinetic energy = Relative charge$\times$ accelerating potential

$KE=1e\times 1kV$

$KE=1keV$

Hence the correct option is C.

As the water heats up from 280 K to 310 K, the average kinetic energy of its molecules will:

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. increase

  2. decrease

  3. stay the same

  4. increase, then decrease

  5. decrease, then increase

Show answer
Correct Option: A
Explanation:

$T$ $\alpha$  $KE$
Higher the temperature higher will be kinetic energy .
Hence, as the water heats up from 280 K to 310 K, the average kinetic energy of the its molecules will increase.

Which of the following is a physical change?

chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

  1. Burning fuel in your car

  2. Baking cookies

  3. Mixing vinegar and baking soda

  4. Respiration (inhaling oxygen gas and exhaling carbon dioxide gas)

  5. Evaporating water

Show answer
Correct Option: E
Explanation:

Evaporation is a physical change because when water evaporates no new substances are being made or nothing is being taken away from it, so in that case its still water. All the other options involve making new substances, so they all are chemical changes. 

Hence, $E$ is correct.

The general formula of carbohydrates is:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. ${C} _{n}{H} _{2n+1}O$

  2. ${C} _{n}{H} _{2n}O$

  3. ${C} _{n}{({H} _{2}O)} _{n}$

  4. ${C} _{n}{({H} _{2}O)} _{2n}$

Show answer
Correct Option: C
Explanation:
The general formula for any carbohydrate is ${(C{H} _{2}O)} _{n} = {C} _{n}{({H} _{2}O)} _{n}$ 

Invert sugar is:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. a type of cane sugar

  2. optically inactive form of sugar

  3. mixture of glucose and galactose

  4. mixture of glucose and fructose in equimolar quantities

Show answer
Correct Option: D
Explanation:
Sucrose which is an equimolar mixture of glucose and fructose on hydrolysis brings about a change in the sign of rotation from dextro (+) to laevo (-) and the product is named as invert sugar.
Hence, invert sugar is a mixture of glucose and fructose in equimolar quantities.

Which of the following compounds is found in abundance in nature?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Fructose

  2. Glucose

  3. Starch

  4. Cellulose

Show answer
Correct Option: D
Explanation:

Cellulose is a type of carbohydrate, containing chains of glucose rings. The cell walls, which are responsible for providing support and rigidity to the plants are made of cellulose. 


It is also the primary constituent of wood, making it the most abundant organic compound found in nature.

Hence, the correct answer is option $\text{D}$.