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19. Intext problems: Calculation based on number of moles from mass and volume I

1.Calculate the number of moles in \(46\) \(g\) of sodium.

Data:

Given mass of sodium \(= 46\) \(g\)

Atomic mass or mass number of sodium \(=\)

Formula:

The formula to find the number of moles from the mass is,

Solution:

By substituting the values in the above formula, we get,

Number of moles \(=\)

2. Calculate the number of moles in \(5.6\) \(L\) of oxygen at STP.

Data:

Given volume of oxygen \(= 5.6\) \(L\)

Molar volume of oxygen at STP \(=\)

Formula:

The formula to find the number of moles from the volume is,

Solution:

By substituting the values in the above formula, we get,

Number of moles \(=\)

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