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Some Basic Concepts Of Chemistry

Question
CBSEENCH11008029
Wired Faculty App

Calculate the number of atoms of each kind in 5·3 g of Na2CO3.

Solution

Formula mass of Na2CO3
                     equals space 2 cross times 23 space plus 12 plus 3 space cross times 16 equals 46 plus 12 plus 48 space equals space 106 space amu
Gram formula mass of Na2CO3 = 106 g
Now 106 g of Na2CO3

equals 6.023 space cross times space 10 to the power of 23 space formula space units space of space Na subscript 2 CO subscript 3 therefore space space space 5.3 space straight g space of space Na subscript 2 CO subscript 3 space equals space fraction numerator 6.023 space cross times space 10 to the power of 23 over denominator 106 end fraction cross times 5.3 space space space space space space space space space space space equals 3.01 space cross times space 10 to the power of 22 space formula space units space of space Na subscript 2 CO subscript 3
Now one formula unit of Na2CO3 contains 2 atoms of sodium, 1 atom of carbon and 3 atoms of oxygen.
therefore space space space N o. space o f space N a space a t o m s space i n space 5.3 space straight g space o f space N a subscript 2 C O subscript 3 space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals 2 space cross times space 3.01 space cross times space 10 to the power of 22 space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space 6.02 space cross times 10 to the power of 22
No of carbon atoms in 5.3 g of Na subscript 2 CO subscript 3
                                       equals space 1 space cross times space 3.01 space cross times space 10 to the power of 22 space equals space 3.01 space cross times space 10 to the power of 22
No. of oxygen atoms in 5.3 g of Na subscript 2 CO subscript 3
                                             equals 3 cross times 3.01 cross times 10 to the power of 22 equals space 9.03 space cross times space 10 to the power of 22

Some More Questions From Some Basic Concepts of Chemistry Chapter

The popular unit of pressure is atmosphere, how is it related to pascal?

What are SI units of the following:

(i) Density    
(ii) Molarity          
(iii) Energy    
(iv) Temperature ?

Out of 5.00 g and 5.0 g which one is more accurate and why?

What is iodised table salt?

Under what conditions air is considered as a heterogenous mixture?

What is gun powder?

Name two elements which are liquids.

Name two elements which are gases.

Name the scientist who proposed the law of multiple proportions.

Is there any exception to the law of constant composition?

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