Tag: general introduction: importance and scope of chemistry

Questions Related to general introduction: importance and scope of chemistry

What is the name given to a pure substance with only one kind of atoms?

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

  1. Element

  2. Compound

  3. Mixture

  4. Suspension

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Correct Option: A
Explanation:

Element is a chemical substance which is composed of same type of atoms or only of single kind e.g., periodic table consist of all elements in its pure form like $Na,\ Mg,\ Cu,\ Pb$ etc.

______ are made up of one kind of atom which can not be broken into simpler substances.

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

  1. Compound

  2. Molecule

  3. Ion

  4. Element

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Correct Option: D
Explanation:

Elements are made up of only one type of atoms which cannot be further broken down.

A compound is a substance composed of two or more different types of _____ chemically combined in a fixed proportion.

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

  1. Element

  2. Compound

  3. Molecule

  4. Ion

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Correct Option: A
Explanation:

Compounds are made up of elements combined in a fixed ratio by mass.

Which of the following is a compound?

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

  1. Iron

  2. Gold

  3. Platinum

  4. Camphor

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Correct Option: D
Explanation:

Iron, gold and platinum are all metallic elements. They are made up of atoms. Camphor on the other hand is a compound made up of elements like C, H and O.

Classify which of the following pair is a compound and a mixture?

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

  1. Air, ocean water

  2. Water, glucose

  3. Glucose, Salt

  4. Water, air

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Correct Option: D
Explanation:

In the above examples, water is a compound and air is mixture. Water consists of oxygen and hydrogen chemically combined whereas air is a mixture which consists of oxygen, nitrogen and other gases which are only physically combined.

In which of these states water can exist?

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

  1. Solid

  2. Liquid

  3. Gas

  4. All of the above

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Correct Option: D
Explanation:

Water exist in all the three states solid as ice, liquid as water and gas as water vapours.

Define element.

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

  1. Can be broken down by chemical reactions into simpler substances

  2. Cannot be broken down by chemical reactions into simpler substances

  3. Maybe be broken down by chemical reactions into simpler substances

  4. Both b and c

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Correct Option: B
Explanation:

A pure substance which is made up of only one kind of atom and cannot be broken into two or more simpler substances by physical or chemical means is referred to as an element. An element is homogeneous in nature; it is a pure substance, made up of only one kind of atoms. For example, iron and silver are made of only iron and silver atoms.

Identify the compounds among the following:


(a) Milk (b) Sodium (c) Calcium Carbonate (d) Methane

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

  1. Milk, Calcium carbonate

  2. Sodium 

  3. Calcium carbonate, Methane

  4. None of the above

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Correct Option: C
Explanation:

Compounds is a pure substance made up of two or more elements combined chemically in a definite (or constant) proportion by mass.


Calcium carbonate is $CaCO _3$, Methane is $CH _4$ --- Compound.

Sodium ----- Element.

Milk ---------- Mixture.

Elements are impure matter. 

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

  1. True

  2. False

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Correct Option: B
Explanation:

Elements are pure substances which are made up of only one kind of atom. All atoms in an element are identical but atoms of different elements are different.

Which of the following is not a compound ?

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

  1. Sugar

  2. Ozone

  3. Benzene

  4. Salt

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Correct Option: B
Explanation:

Compound is made up of two or more elements. Ozone is made up of 3 oxygen atoms which are identical. Hence, its an element and not a compound.