Tag: general introduction: importance and scope of chemistry

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Multiple choice evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

Carbon dioxide is associated with:

  1. Elements

  2. Mixture

  3. Compound

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon dioxide is a naturally occurring chemical compound composed of 2 oxygen atoms each covalently double bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state, as a trace gas at a concentration of $0.04 \%$ by volume.

Multiple choice evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

Example of an element is:

  1. Water

  2. Sodium hydroxide

  3. Hydrogen

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

A chemical element is a pure chemical substance consisting of a single type of atom distinguished by its atomic number, which is the number of protons in its atomic nucleus. If you change the number of protons an atom has, you change the type of element it is.

Here, hydrogen is an element while water, sodium hydroxide and sugar are compounds made up of more than elements.

Multiple choice evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

Classification of matter helps us to:

  1. study things systematically

  2. share information with others

  3. know the properties of all the members of a group if we know about one

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Classification of matter helps us to:


(i) Know the properties of all members of a group if we know about one.


(ii) Study things systematically.

(iii) Share information with others.


Option D is correct.

Multiple choice evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

Which among the following is associated with iron sulphide ?

  1. Element

  2. Mixture

  3. Compound

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Iron(II) sulfide or ferrous sulfide is a chemical compound with the formula $FeS$. Iron sulfides are often non-stoichiometric. powdered iron sulfide is pyrophoric (ignites spontaneously in air).

Multiple choice evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

The property that we use for classifying things depends on the ___________ of the classification.

  1. grouping

  2. purpose

  3. information

  4. system
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Things are always classified to make 

(i)easy identification of things.
(ii)Can know all properties of group if we know about one element in the group.
The property that we use  for classifying things depend on the purpose of classification.

Multiple choice evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

Which of the following is not a compound?

  1. Sulphur dioxide

  2. Chalk

  3. Lead

  4. Sulphuric acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lead $(Pb)$ is not a compound. It is an element present in its pure form so it a single homogeneous identity. Compounds have two or more elements present in the uniform composition in the compound state.


Sulphur dioxide $(SO _2)$ is formed by two elements namely, sulphur and oxygen.

Sulphuric acid $(H _2SO _4)$ is a compound formed by hydrogen, sulphur and oxygen.
The chemical formula for chalk is CaCO3 which is made up of carbon, calcium and oxygen.

Hence, option $C$  is correct.