Tag: chemistry

Questions Related to chemistry

When a vehicle travels very fast, a region of ______ is created temporarily just behind it.

chemistry air, winds and cyclones the concept of bernoulli's principle air exerts pressure wind and pressure variations in atmospheric pressure wind and rain uneven heating of earth

  1. High pressure

  2. Low pressure

  3. High density

  4. Cyclone

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Correct Option: B
Explanation:
When a vehicle moves very fast, a low pressure is produced temporarily and the wind nearby rushes in to fill its place.

Which of the following principle shows that if you increase air speed its pressure will decrease?

chemistry air, winds and cyclones the concept of bernoulli's principle air exerts pressure wind and pressure variations in atmospheric pressure wind and rain uneven heating of earth

  1. Darwin principle

  2. Einstein principle

  3. Bohr principle

  4. Bernoulli's principle

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Correct Option: D
Explanation:
According to Bernoulli's principle, Fast moving air equals low air pressure while slow moving air equals high air pressure.
 Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. The same is applicable in case of gases also.

Increase in air speed is associated with ______________ .

chemistry air, winds and cyclones the concept of bernoulli's principle air exerts pressure wind and pressure variations in atmospheric pressure wind and rain uneven heating of earth

  1. increasein air pressure

  2. decrease in air pressure

  3. increase in air temperature

  4. decrease in air temperature

Show answer
Correct Option: B
Explanation:
The increased wind speed is accompanied by a reduced air pressure.

A piece of paper is kept on the table.  You have to lift it from the table by blowing high-speed air over it. In which direction will you blow the air?

chemistry air, winds and cyclones the concept of bernoulli's principle air exerts pressure wind and pressure variations in atmospheric pressure wind and rain uneven heating of earth

  1. Sideways

  2. In the upward direction

  3. In the downward direction

  4. In the upward direction below the table

Show answer
Correct Option: A
Explanation:
In order to lift the paper up from the table we need to blow air in sideways.

Two pieces of papers are held parallel. Air is blown with a high speed in between them. Which of the following phenomena will be observed?

chemistry air, winds and cyclones the concept of bernoulli's principle air exerts pressure wind and pressure variations in atmospheric pressure wind and rain uneven heating of earth

  1. The papers will move away from each other.

  2. The papers will move towards each other.

  3. The papers will stay at their position.

  4. The papers will catch fire due to increase in air temperature.

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Correct Option: B
Explanation:
It seems amazing that the two sheets of paper move closer together, the pressure is reduced where the air is moving quickly. This is called the Bernoulli principle. 

Tertiary alcohol on treatment with cyanide in presence of conc. ${ H } _{ 2 }{ SO } _{ 4 }$ gives corresponding primary amine. This reaction is called as :

chemistry hydroxy compounds and ethers alcohol nomenclature of alcohols and phenols introduction to alcohols

  1. Schmidt reaction

  2. Curtius degradation

  3. Leuckart reaction

  4. Ritter reaction

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Correct Option: B

In the reaction 2A+B --> 2C + D , 5 mol/lt of 'A; are allowed to react with 3mol/lt of B.After 5 seconds the concentration of A was found to be 4 molar What is the rate of reaction in terms of A>

chemistry hydroxy compounds and ethers alcohol nomenclature of alcohols and phenols introduction to alcohols

  1. 0.1 m/sec

  2. 0.2

  3. 0.3

  4. 0.15

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Correct Option: B

Ideal fuel should have high calorific value.

chemistry chemical thermodynamics calorific value occurrence of carbon compounds in nature study of enthalpy

  1. True

  2. False

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Correct Option: A
Explanation:

Calorific value is defined as heat produced by complete combustion of a specific quantity of a fuel . It is usually expressed in joules per kilogram. An ideal fuel is one which is having high calorific value.

What is used to measure the calorific value of a substance?

chemistry chemical thermodynamics calorific value occurrence of carbon compounds in nature study of enthalpy

  1. Barometer

  2. Bomb calorimeter

  3. Spectrometer

  4. Combustion chamber

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Correct Option: B
Explanation:

Barometer: To measure pressure.

Bomb calorimeter: To measure the heat output of combustion.

Spectrometer: To measure the absorption of light.

Combustion chamber: Chamber used for combustion.

What is the unit of calorific value?

chemistry chemical thermodynamics calorific value occurrence of carbon compounds in nature study of enthalpy

  1. kJ/kg

  2. kJ/lit

  3. km/hr

  4. kcal

Show answer
Correct Option: A
Explanation:

Calorific value is defined as the amount of energy released during combustion per unit mass of the substance.