Question

Some Basic concept of Chemistry
Q1. Why do atomic masses of most of the elements in atomic mass unit involve fraction?
Q2. Calculate the mass of 3 g molecules of nitric acid.
Q3. How many moles of magnesium are present in 0.478 g of element ?
Q4. Calculate mass of a molecule of fluorine, which occurs as two atoms per molecule.
Q5.Calculate the number of oxygen atoms in 300 g of CaCO3
Q6. What is the average mass of molecule of methane ?​

Answer 1

Here Is Your Ans

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1 => The atomic masses of most elements are fractional because they exist as a mixture ofisotopes of different masses. ... Most elements occur as a mixture of isotopes of different masses. The fractional atomic masses arise because of this mixture.

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2 => molar mass of Nitric Acid (HNO3) = 1 + 14 + 48 = 63 g

3 moles = 3 x 63 g = 189 grams. That would be the mass

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3 => Molecular weight of magnesium =24g

24g of magnesium = 1 mole

0.478g of magnesium = ----- moles.

= 0.478 X 1/24 =0.019 moles

4 => ×

5 => ×

6 => ×

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Answer 2

Explanation:

0 .1999 is the average mass of molecules of meathane