Question

how many gram of H2O are produced in burning2.5dm*3 of h2 at stp​

Answer 1

Concepts Involved -

=> The concept of molar mass is used here, it is the number of grams in 1 mole of any substance, it is numerically equal to the sum of the individual atomic masses of the elements present in the compound.

=> Also, 1 mole of any gas at STP (Standard Temperature & Pressure) has a volume of 22.4 litres or 22.4 dm³

Reaction taking place -

• Balanced Chemical Equation -

        2H₂ + 1O₂ ----> 2H₂O

• From this we understand -
• 2 volumes of Hydrogen gas react with 1 volume of Oxygen gas to give 2 volumes of water vapour (H₂O)

Given -

=> 2.5 dm³ of H₂ are burnt completely, at STP.

∵ 22.4 dm³ of gas at STP is 1 mole

∴ 2.5 dm³ of gas at STP is $\dfrac{2.5}{22.4}$ moles => 0.1116 moles of H₂

Comparing with the equation -

∵ 2 volumes of H₂ react with 1 volume of O₂ to give 2 volumes of water vapour.

=> We know that 0.1116 moles of H₂ are present -

=> 2 volumes of H₂ = 0.1116 moles of H₂

=> 1 volume of H₂ = 0.1116/2 moles => 0.0558 moles of H₂

=> Thus, 2 volumes of water vapour are 0.0558 * 2 => 0.1116 moles of H₂O

=> Now, we know that the molar mass of H₂O is 2 * 1 + 16 => 2 + 16 = 18

=> Molar mass of H₂O = 18 grams per mole

=> So, 0.1116 moles of H₂O has a mass of 0.1116 * 18 grams => 2.0088 grams

Answer -

=> The mass of H₂O formed will be - 2.0088 grams

More to refer to -

=> A similar question about molar mass, Limiting Reagent and more -

https://brainly.in/question/37988652