Some chemical equations are given. C + O 2 → CO 2 CH 4 + 2 O 2 → CO 2 + 2 H 2 O N 2 + O 2 → NO CaCO 3 → CaO + CO 2 H 2 + I 2 → HI Fe + HCl → FeCl 2 + H 2 CO 2 + C → CO Which of these are balanced chemical equations?

When an equal number of atoms of an element is present on both sides of a chemical equation, the equation is balanced. Thus, balanced equations from the given equations are as follows: C + O 2 → CO 2 CH 4 + 2 O 2 → CO 2 + 2 H 2 O CaCO 3 → CaO + CO 2

Some chemical equations are given. C + O 2 → CO 2 CH 4 + 2 O 2 → CO 2 + 2 H 2 O N 2 + O 2 → NO CaCO 3 → CaO + CO 2 H 2 + I 2 → HI Fe + HCl → FeCl 2 + H 2 CO 2 + C → CO Balance those equations which are not balanced.

The equations that are not balanced are: N 2 + O 2 → NO H 2 + I 2 → HI Fe + HCl → FeCl 2 + H 2 CO 2 + C → CO Thus, the balanced equations for the above unbalanced equations are as follows: N 2 + O 2 → NO can be balanced and rewritten as: N 2 + O 2 → 2 NO H 2 + I 2 → HI can be balanced and rewritten as: H 2 + I 2 → 2 HI Fe + HCl → FeCl 2 + H 2 can be balanced and rewritten as: Fe + 2 HCl → FeCl 2 + H 2 CO 2 + C → CO can be balanced and rewritten as: CO 2 + C → 2 CO

E M B I B E

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 3

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IMPORTANT

Earn 100

N is the symbol of nitrogen.

How many molecules and atoms are present in $5 N_{2}$ ?

Important Questions on Basic Constituents of Matter

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 4

Some chemical equations are given.

$C + O_{2} \to {CO}_{2} {CH}_{4} + 2 O_{2} \to {CO}_{2} + 2 H_{2} O N_{2} + O_{2} \to NO {CaCO}_{3} \to CaO + {CO}_{2} H_{2} + I_{2} \to HI Fe + HCl \to {FeCl}_{2} + H_{2} {CO}_{2} + C \to CO$

Which of these are balanced chemical equations?

MEDIUM

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 4

Some chemical equations are given.

$C + O_{2} \to {CO}_{2} {CH}_{4} + 2 O_{2} \to {CO}_{2} + 2 H_{2} O N_{2} + O_{2} \to NO {CaCO}_{3} \to CaO + {CO}_{2} H_{2} + I_{2} \to HI Fe + HCl \to {FeCl}_{2} + H_{2} {CO}_{2} + C \to CO$

Balance those equations which are not balanced.

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 5

All atoms of the same element show the same properties.

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 5

The atoms present in a compound are different.

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 5

Elements are pure substances.

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Let us assess>Q 5

Hydrogen is a monatomic molecule.

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IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Extended activities>Q 1

Haven’t you understood how symbols are assigned to elements? Given below are some elements that received symbols from their Latin names. Complete the table with the help of the Periodic Table.

Element	Latin name	Symbol
Silver	....................	...................
............	Hydrargium	..................
Tin	...............	.................
.................	...................	Pb
Antimony	..................	...................
..................	Aurum	.................