Tag: chemistry

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

  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.
Reveal answer Fill a bubble to check yourself
A,C Correct answer
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.
Multiple choice chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. Oxygen

  2. Carbon dioxide

  3. Chlorine

  4. Nitrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

The three elements most usually contained in fertilizers are:

  1. Potassium, phosphorus and carbon

  2. Sodium, nitrogen and phosphorus

  3. Silica, nitrogen and phosphorus

  4. Potassium, phosphorus and nitrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
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;

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

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

  1. carbon dioxide

  2. hydrogen

  3. nitrogen

  4. oxygen
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

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

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

Plasma state contain ionized gas particles.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. $-273^0C$
  2. $273^0C$
  3. $273K$
  4. $295K$
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. plasma

  2. Bose-Einstein condensate

  3. solid

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. great amounts of energy

  2. great amounts of liquid

  3. another gas

  4. water

  5. great amounts of time
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Plasma state refers to:

  1. super cooled gaseous state

  2. super heated gaseous state

  3. super cooled liquid state

  4. super heated liquid state
Reveal answer Fill a bubble to check yourself
B Correct answer
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.