Question

i) find the mass of 10 moles of sodium sulphate (Na2SO4) i) Calculate the number of molecules in 8g of oxygen gas. iii) convert 22g of CO2 into moles​

Answer 1

Ques 1). Find the mass of 10 moles of sodium sulphate (Na2SO4).

→ Mass of Na2SO4 = 2 (mass of Na) + mass of sulpher + 4 (mass of oxygen)

→ Mass of Na2SO4 = 2 (23) + 32 + 4 (16)

→ Mass of Na2SO4 = 142 g

So, 142 g is mass of Na2SO4 of one mole.

→ Mass of 10 moles of Na2SO4 = 142 × 10

→ Mass of 10 moles of Na2SO4 = 1420 g

Hence, mass of 10 moles of sodium sulphate is 1420 g.

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Ques 2). Calculate the number of molecules in 8g of oxygen gas

→ Number of molecules = (Given mass/Molecular mass) × Avagadro's number

→ Number of molecules = (8/16) × 6.022 × 10²³

→ Number of molecules = 3.011 × 10²³

Hence, number of molecules in 8 g of oxygen is 3.011 × 10²³

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Ques 3). Convert 22g of CO2 into moles.

→ Mass of one mole of CO2 = 12 + 2(16)

→ Mass of one mole of CO2 = 12 + 32

→ Mass of one mole of CO2 = 44 g

Now, we've to find number of moles.

→ Moles = given mass/molecular mass

→ n = 22/44

→ n = 0.5

Hence, 0.5 moles are present in 22 g of CO2.

Answer 2

Answer:

Ques 1). Find the mass of 10 moles of sodium sulphate (Na2SO4).

→ Mass of Na2SO4 = 2 (mass of Na) + mass of sulpher + 4 (mass of oxygen)

→ Mass of Na2SO4 = 2 (23) + 32 + 4 (16)

→ Mass of Na2SO4 = 142 g

So, 142 g is mass of Na2SO4 of one mole.

→ Mass of 10 moles of Na2SO4 = 142 × 10

→ Mass of 10 moles of Na2SO4 = 1420 g

Hence, mass of 10 moles of sodium sulphate is 1420 g.

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Ques 2). Calculate the number of molecules in 8g of oxygen gas

→ Number of molecules = (Given mass/Molecular mass) × Avagadro's number

→ Number of molecules = (8/16) × 6.022 × 10²³

→ Number of molecules = 3.011 × 10²³

Hence, number of molecules in 8 g of oxygen is 3.011 × 10²³

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Ques 3). Convert 22g of CO2 into moles.

→ Mass of one mole of CO2 = 12 + 2(16)

→ Mass of one mole of CO2 = 12 + 32

→ Mass of one mole of CO2 = 44 g

Now, we've to find number of moles.

→ Moles = given mass/molecular mass

→ n = 22/44

→ n = 0.5

Hence, 0.5 moles are present in 22 g of CO2

Explanation: