Chemistry · Science General

States of Matter

2,382 Questions

States of matter questions explore physical changes, evaporation, phase transitions, and the properties of liquids and gases. Topics cover density, cryosurgery, heavy water, and electrolytes. This foundational chemistry topic frequently appears in general science sections of SSC and railway exams.

Phase change mechanismsEvaporation and temperature effectsProperties of liquidsPhysical versus chemical changesElectrolytes and heavy water

States of Matter Questions

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Identify the substance that evaporates at room temperature.

  1. Water

  2. Oil

  3. Kerosene

  4. Ammonium chloride
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Kerosene is more volatile than water and oil, meaning it evaporates more readily at room temperature due to weaker intermolecular forces between its molecules. While water does evaporate at room temperature (that's why puddles dry), kerosene has a higher vapor pressure and evaporation rate. Oil has the strongest intermolecular forces and evaporates very slowly. Ammonium chloride sublimates (solid to gas) rather than evaporates (liquid to gas).

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Dissolution of carbon dioxide gas in water is  ________ change.

  1. chemical

  2. physical
  3. both of $A$ and $B$

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Dissolution of carbon dioxide gas in water is both a physical and chemical change.
Carbon dioxide dissolves in water producing carbonic acid, also known as soda water.
$ CO _2 + H _2O\rightarrow H _2CO _3$
There will be an equilibrium constant that will dictate the relative concentration of dissolved gas to the corresponding acid that is formed.
Usually nonmetal oxides like$CO _2, SO _2, NO _2$  simply dissolve in water, depending on the partial pressure above the water, and Henrys law constant. This implies a physical change.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Melting of wax is a _________ change.

  1. physical

  2. chemical
  3. both $A$ and $B$

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

No new substances are formed. In a burning candle, there are both physical and chemical changes. The melting of the solid wax to form liquid wax and the evaporation of liquid wax to form wax vapour are physical changes. The burning of the wax vapour is a chemical change.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

In ___________ , the properties of molecules remain same even after the change.

  1. physical change

  2. chemical change

  3. biochemical change

  4. photochemical change
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A physical change is any change in matter that involves the substance going from one physical state to another. 

The reference to a physical state involves solids, liquids, and gases. When a substance undergoes a physical change it does not lose its original properties because no new formation takes place when changing from one phase to another. The types of physical changes can vary. A substance can go from a solid to a liquid, a liquid to a gas, a gas to a liquid, a liquid to a solid, a solid to a gas, or a gas to a solid.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

$Ice\underset {cooling}{\overset {heating}{\rightleftharpoons}} water \underset {cooling}{\overset {heating}{\rightleftharpoons}} steam$. Identify the type of change

  1. Physical change

  2. Chemical change

  3. Both physical and chemical changes

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the given example, water only changes its state by the change in temperature, but its properties remain same hence it is an example of physical change not a chemical change.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Boiling water is a _____ change because _____.

  1. Physical, the gaseous water produced is chemically identical to the liquid water the process began with

  2. Physical, the water was disappeared

  3. Chemical, heat was required for the change

  4. Chemical, the process produced a gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Boiling water is a physical change because the gaseous water produced is chemically identical to the liquid water i.e both of them have the same molecular structure of the water.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

According to the CRC's  the melting point of cadmium bromide is $868^{\circ}C$. Which of the following equations best describes what occurs when cadmium is heated to $868^{\circ}C$?

  1. $CdBr(s)\rightarrow CdBr(l)$
  2. $CdBr _{2}(s)\rightarrow CdBr _{2}(l)$
  3. $CdBr _{2}(s)\rightarrow Cd(s) + Br _{2}(g)$
  4. $CdBr _{2}(s)\rightarrow Cd^{2+}(aq) + 2Br^{-}(aq)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Heating a solid substance to its melting point causes a phase transition from the solid state to the liquid state without chemical decomposition. Therefore, solid cadmium bromide transforms into liquid cadmium bromide at 868 degrees Celsius.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Your lab partner mixed two colorless solutions in the test tube. He sees no observable changes in the resulting mixture and is unable to detect any change in temperature. Based on these observations, what type of reaction has taken place?

  1. A physical reaction

  2. A chemical reaction

  3. An exothermic reaction

  4. An endothermic Reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When two solutions are mixed and no observable changes like evolution of gas or precipitate formation takes place then the reaction is reversible and the reaction is a physical reaction.

Ans :- A

Multiple choice chemistry change around us physical changes changes and their classification physical changes

The melting point of cadmium bromide is $568^{\circ}C$. Which of the following equations best describes what occurs when cadmium bromide is heated to $568^{\circ}C$?

  1. $CdBr(s)\rightarrow CdBr(l)$
  2. $CdBr _{2}(s)\rightarrow CdBr _{2}(l)$
  3. $CdBr _{2}(s)\rightarrow Cd(s) + Br _{2}(g)$
  4. $CdBr _{2}(s) \rightarrow Cd^{2+} (aq) + 2Br^{-}(aq)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Melting point is defined as the temperature at which solid is converted to liquid.

Given, Melting point of $Cd{ Br } _{ 2 }={ 568 }^{ 0 }C$

So, At ${ 568 }^{ 0 }C$

${ CdBr } _{ 2 }\left( solid \right) \longrightarrow { CdBr } _{ 2 }\left( liquid \right) $
Ans :- A

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Your lab partner mixed two colorless solutions in the test tube. He sees no observable changes in the resulting mixture and is unable to detect any change in temperature. Based on these observations, what type of reaction has taken place?

  1. A physical reaction

  2. A chemical reaction

  3. An exothermic reaction

  4. No reaction has taken place
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

No change in temperature $-$ neither exothermic  or endothermic reaction.

as no observable change $-$  not a chemical reaction
since the liquid mixed $-$ it is a physical change.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Dissolving sugar in water is an example of:

  1. physical change

  2. chemical change

  3. neutralisation

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

Sugar dissolves in water is a physical change because in this change no new substance is formed and the process is reversible in which by vaporization followed by condensation and crystallization water and sugar can be separated.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

If the substance is expanded on melting, the melting point ______ when the pressure is increased.

  1. increases

  2. decreases

  3. remains same

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

If the substance is expanded on melting, the melting point increases when the pressure is increased, because in increased pressure substance try to be in a state where volume decreases.