Question

Example 8. Calculate the mass of (i) 0.1 mole
of KNO, (ii) 1 X 1023 molecules of methane and
(iii) 112 cm of hydrogen at STP.​

Answer 1

Answer:

Here's yours answer

(a) The molar mass of KNO3 is 101 g/mol. Thus

1 mole of KNO3 = 101 g

Therefore 0.1 mole of KNO3 = 0.1×101 g = 10.1 g

(b) The molar mass of methane (CH4) is 16 g. As there are 6.022×1023 molecules in 1 mole of methane, therefore

6.023×1023 molecules of methane = 16 g of methane

1 molecule of methane = (16 / 6.022 × 1023 ) g of methane

1023 molecules of methane = (16×1023 ) / 6.022×1023 g of methane

= 2.657 g

(c) 112 cm3 of hydrogen, H2 at STP.

1 mole of hydrogen at STP occupy 22.4 L or 22400 cm3 volume and mass 2 g.

Mass of 22400 cm3 of hydrogen = 2 g

Mass of 112 cm3 of hydrogen = (2/22400) × 112 = 0.01008

Answer 2

Step-by-step explanation:

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