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Showing posts with label SOME BASIC CONCEPT OF CHEMISTRY. Show all posts
Showing posts with label SOME BASIC CONCEPT OF CHEMISTRY. Show all posts
Tuesday, August 29, 2023

Average molar weight (Molecular weight): or Mean Molecular Mass

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We know that for gas: Pressure fraction = Mole fraction= Volume fraction Pressure % = Mole % = Volume % Consider mixture of two different ga...

Vapour density of mixture of NO2 ​and N2O4 ​ is 34.5, then percentage abundance of NO2 ​ in mixture is:

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 Answer Key: 50 %

A gaseous mixture of H2 ​and CO2 ​contains 66 mass % of CO 2 ​ The vapour density of the mixture is:

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 Answer Key: VD :2.7

The vapour density of a mixture containing NO2 and N2O4 is 27.6 . Mole fraction of NO2 in the mixture is:

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Answer Key: 0.2 Mole

N2O4 on decomposition gives its monomer NO2 and they are found to be in equilibrium at 300 K. if the VD of such a mixture is 41.4 the calculate % composition by (1) Moles of NO2 and N2O4 (2) By mass O2

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Answer Key: (1) 20% and 80% (2) 11.1%

A compound of nitrogen and oxygen was found to contain 7: 16 by mass N and O respectively. Calculate molecular formula if vapour density is 46.

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 Answer Key: ( N2O4)

A mixture of blue and green balls contains 25% by number blue balls. Mass of each blue balls is 40 gm and mass of each green balls is 20 gm calculate (1) Average mass of ball (2) % by mass

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Answer Key: (1) 25 gm (2) 40 %

Air contains 20% of O2 and 80 % N2 by moles find the average molecular mass weight and % by mass of oxygen and nitrogen.

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Answer Key:   Mav = 23.8 amu ,  %  by mass of Oxygen =  22.3 %  and % by mass of Nitrogen is 77.7 % 

An element X have three isotopes X ^20 ,X ^21 and X ^22 . The percentage abundance of X^20 is 90% and the average atomic mass of element is 20.18. The percentage abundance of X ^21 should be

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 Answer Key: 2%

Calculate Average atomic mass of Argon the natural abundance % of isotopes of Argon is given as:

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Answer Key: 39.94 amu

Calculate the average atomic mass of silicon if relative abundance is 92.23 ,isotope Si^28, 4.77 % isotope = Si^29 and 3% isotope = Si^39 .

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Answer Key:   The average atomic mass of silicon is 28.1 amu

Silver contains two isotopes Ag 107 and Ag109 and average atomic weight of silver is 108.5 find percentage abundant of isotopes of silver.

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  Answer Key: Ag (107) 25% and Ag (109) 75%

Boron have two isotopes B11 and BA and their relative abundant % are 80% and 20% respectively and average atomic weight of Boron is 10.8 find the value of “A”

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  Answer Key:  A= 10

Natural hydrogen gas is a mixture of 1H and 2H in the ratio of 5000:1. Calculate the atomic mass of the hydrogen.

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  Answer Key: 1.000199 amu

Carbon occurs in nature as a mixture of carbon 12 and carbon 13. The average atomic mass of carbon is 12.011. What is the percentage abundance of carbon 12 in nature?

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SOLUTION:

Calculate the molar mass of naturally occurring argon. Using the date given in the following table to ..

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  SOLUTION: Molar mass of Ar = 35.96755 × 0.071 + 37.96272 × 0.163 + 39.96924 × 0.766 = 39.352 g mol −1  

Average Atomic Mass/weight or Relative Atomic Mass:

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Elements are found in different isotopic forms (atoms of same elements having different atomic mass), so the atomic mass of any element is t...
Friday, May 19, 2023

5.7 g of bleaching powder was suspended in 500 mL of water. 25 mL of this suspension on treatment with KI and HCl liberated iodine which reacted with 24.35 mL of 10N​ Na2​S2​O3​. Calculate the percentage of available chlorine in bleaching powder.

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Answer Key: 30.33 %
Thursday, May 18, 2023

A metal carbonate on heating is converted to metal oxide and is reduced to 60% of its original weight. The equivalent weight of the metal is

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Answer Key: 25
Sunday, May 14, 2023

A plant virus is found to consist of uniform cylindrical particle of 150 Angstrom in diameter and 5000 Angstrom long. The specific volume of the virus is 0.75 mL g−1. if the virus is considered to be a single particle, find its molar mass.

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Answer key : 7.092×10^7