Tag: chemistry

Questions Related to chemistry

In which of the following compounds resonance does not occur
(i) ${H _2}O$
(ii) $Si{O _2}$
(iii) $S{O _3}$
(iv) $C{O _2}$

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Both (i) and (iv)

  2. Both (i) and (ii)

  3. Both(iii) and (iv)

  4. (i),(ii)and(iv)

Show answer
Correct Option: D

Which of the following is/are example(s) of mixtures?

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Air

  2. $Fe + S$

  3. Bronze

  4. All of the above

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Correct Option: D
Explanation:

Air is a mixture of gases. $Fe + S$ is also a mixture. Bronze is an alloy and all alloys are mixtures.

A compound is always ______ whereas a mixture is :

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Heterogenous, both heterogenous and homogenous

  2. Homogenous, heterogenous

  3. Homogenous, Both homogenous and heterogenous

  4. None of above

Show answer
Correct Option: C
Explanation:

Compound is made up of two or more pure substances which are always homogenous. Mixtures contains two or more pure substances physically combined which may be homogenous or heterogenous

Which of the following is a pure gas?

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Ntural gas

  2. Water gas

  3. Laughing gas

  4. Coal gas

Show answer
Correct Option: C
Explanation:

Pure gas is not a mixture.


Natural gas consists of a mixture of gases like methane, higher alkanes, carbon dioxide etc. So it is not a pure gas.

Similarly, water gas is a mixture of $CO, H _2S$
Coal gas is a mixture of $H _2,CH _4,CO$
But laughing gas is only $N _2O$, So it is pure gas.


Hence, the correct option is $C$

Which of the following obey the law of constant proportions in their formation?

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Mixtures

  2. Compounds

  3. Elements

  4. Colloids

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Correct Option: B
Explanation:

A compound always follow the law of constant proportions because in a compound the elements that are present are always in the constant ratio.

Among the following, which is\are the difference between compound and mixture?

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. The constituents of a compound can be separated only by chemical methods.

    The constituents of a mixture can be separated easily by physical methods.

  2. Compounds are pure substances.

    Mixtures are impure substances.

  3. The constituents of a compound are present in a fixed ratio.

    The constituents of a mixture are present in varying ratios.

  4. All of above

Show answer
Correct Option: D
Explanation:

Compounds are pure substances whereas mixture are impure substances. The constituents of a compound can be separated only by chemical methods and that of a mixture can be separated easily by physical methods. The constituents of a compound are present in a fixed ratio.The constituents of a mixture are present in varying ratios.

_____is chemically mixed whereas____is physically combined.

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Element, compound

  2. Compound, mixture

  3. Mixture, compound

  4. Mixture, element

Show answer
Correct Option: B
Explanation:

Compound is made up of two or more elements that are chemically combined whereas mixtures are made up of two or more pure substances that are physically combined. 

Which of the following is not a property of mixtures?

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Components of mixtures are present in a varying proportions

  2. They are always homogeneous

  3. The components of mixtures retain their original properties

  4. The components of mixtures can be separated by physical means

Show answer
Correct Option: B
Explanation:

Mixtures can be homogeneous or heterogeneous. Oil and Water is a heterogeneous mixture.

Which of the following methods can be used to separate hydrogen and oxygen in water?

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Boiling

  2. Electrolysis

  3. Distillation

  4. None of the above

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Correct Option: B
Explanation:

Electrolysis decomposes the water into oxygen and hydrogen due to passage of electric current.

Each component of a ______ retains its individual properties.

chemistry pure substances and mixtures: separation of mixtures difference between mixtures and compounds pure substance and mixtures types of pure substances

  1. Compound

  2. Element

  3. Mixture

  4. Solute

Show answer
Correct Option: C
Explanation:

Matter that consists of two or more substances which may be elements, compounds or both mixed together physically in any proportion, but not chemically combined is called as a mixture. Each component of a mixture retains its individual properties. 

For example, we could mix various proportions of hydrogen and oxygen gas, as long as you do not ignite the mixture, the combination will form a mixture that can be separated.