Which will have a greater mass of hydrogen, a 10.0 gram sample of water, or a 20.0 gram sample of water?

20 gram of sample of water will have greater mass of hydrogen.

Explanation:

To calculate the number of moles, we use the equation:

     .....(1)

The chemical formula for water is

Given mass of water = 10 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

In 1 mole of water, 2 moles of hydrogen and 1 mole of oxygen atoms are present.

Moles of hydrogen =

Calculating the mass of hydrogen in 0.55 moles of water by using equation 1, we get:

Molar mass of hydrogen atom = 1 g/mol

Moles of hydrogen atom = 1.11 moles

Putting values in equation 1, we get:

Mass of hydrogen atom = 1.11 g

Given mass of water = 20 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

In 1 mole of water, 2 moles of hydrogen and 1 mole of oxygen atoms are present.

Moles of hydrogen =

Calculating the mass of hydrogen in 1.11 moles of water by using equation 1, we get:

Molar mass of hydrogen atom = 1 g/mol

Moles of hydrogen atom = 2.22 moles

Putting values in equation 1, we get:

Mass of hydrogen atom = 2.22 g

Hence. 20 gram of sample of water will have greater mass of hydrogen.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

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