Tag: chemistry

Questions Related to chemistry

Nitrogen is used in high-temperature thermometer :
chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

  1. To prevent vaporization of mercury.

  2. To improve conductivity of mercury.

  3. To maintain mercury to remain in its state.

  4. To increase the specific heat capacity of mercury.

Show answer
Correct Option: A,C
Explanation:
The principle used to measure temperature is that of the apparent thermal expansion of the liquid. An inert gas is used for mercury intended to high temperature. The thermometer is filled with an inert gas such as argon or nitrogen above the mercury to reduce its volatilization.

Hence, both options (A) and (C) are correct.

State True or False.
Liquid nitrogen is used as a refrigerant to preserve biological specimens.

chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Liquid nitrogen is used as a refrigerant to preserve biological specimens because of its low temperature (-196$^o$) that does not cause cell breakdown or affect any other cellular mechanisms.

The potato chips manufacturers uses _____ gas to flush the chips bags to prevent the chips getting oxidised.

chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

  1. Oxygen

  2. Carbon dioxide

  3. Chlorine

  4. Nitrogen

Show answer
Correct Option: D
Explanation:

Oil and fat containing food items are flushed with nitrogen because the food containing fats and oil become rancid after sometime because of oxidation and give smell having a bad taste. Presence of nitrogen helps food to save from rancidity.

The three elements most usually contained in fertilizers are:

chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

  1. Potassium, phosphorus and carbon

  2. Sodium, nitrogen and phosphorus

  3. Silica, nitrogen and phosphorus

  4. Potassium, phosphorus and nitrogen

Show answer
Correct Option: D
Explanation:

Fertilizers are composed of three macronutrients, $NPK$ nitrogen, phosphorous and potassium.

Nitrogen ($N$): Leaf growth;
Phosphorus ($P$): Development of roots, flowers, seeds, fruit;
Potassium ($K$): Strong stem growth, movement of water in plants, promotion of flowering and fruiting;

Lime water turns milky when exposed. to air and stirred. This shows that air contains:

chemistry air and atmosphere natural cycles and resources constituents of air component of air - nitrogen

  1. carbon dioxide

  2. hydrogen

  3. nitrogen

  4. oxygen

Show answer
Correct Option: A
Explanation:

Lime water turns milky when exposed to air and stirred as lime water mixes with $CO _{2}$ and forms $CaCO _{3}$ (calcium carbonate) which turns the lime water milky. 

$CaO+CO _{2} \longrightarrow CaCO _{3}$

Plasma state contain ionized gas particles.

chemistry element, compound and chemical reaction materials around us materials around us and different types of houses matter and its states

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Plasma state is obtained by heating gases to very high temperature. During heating of the gases, the electrons get extracted from the atom. Because of this the formation of the positively charged nucleus and negatively charged electrons takes place in the gas. This causes ionization of the gas.

Bose-Einstein condensate state is obtained by cooling of the substance below _____.

chemistry element, compound and chemical reaction materials around us materials around us and different types of houses matter and its states

  1. $-273^0C$

  2. $273^0C$

  3. $273K$

  4. $295K$

Show answer
Correct Option: A
Explanation:

Bose-EInstein condensate (BEC) is the fifth state of matter which is obtained by supercooling of the substance below $-273^0C$. This state of matter is artificially prepared in a laboratory because it is difficult to obtain such a low temperature naturally.

The shining of the sun and stars is due to the __________ state of matter.

chemistry element, compound and chemical reaction materials around us materials around us and different types of houses matter and its states

  1. plasma

  2. Bose-Einstein condensate

  3. solid

  4. none of these

Show answer
Correct Option: A
Explanation:

The shining of the sun and stars is due to the plasma state of matter. The plasma state causes ionization of the gases which causes shining of the substance.

Gas can be turned into a plasma on earth with the addition of:

chemistry element, compound and chemical reaction materials around us materials around us and different types of houses matter and its states

  1. great amounts of energy

  2. great amounts of liquid

  3. another gas

  4. water

  5. great amounts of time

Show answer
Correct Option: A
Explanation:

Plasma is called fourth state of matter. In this state every substance remains in gaseous state, this gas has only ions and free electrons. This state is obtained by freeing all the electrons from the attraction of nucleus. To make the electrons free from nucleus we have to give them energy equal to or greater than the energy by which they are bound with nucleus, therefore for that we require a great amount of energy.

Plasma state refers to:

chemistry element, compound and chemical reaction materials around us materials around us and different types of houses matter and its states

  1. super cooled gaseous state

  2. super heated gaseous state

  3. super cooled liquid state

  4. super heated liquid state

Show answer
Correct Option: B
Explanation:

Plasma state refers to the super heated gaseous state.
Plasma state is obtained by heating a gas above 5000 $^o$C. The number of electrons in the atoms or molecules decreases or increases, to form positively or negatively charged ions and also the molecular bond breaks.