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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Spitzchan on November 27, 2024, 07:13:07 AM

Title: Molar Mass
Post by: Spitzchan on November 27, 2024, 07:13:07 AM

I'm not understanding these two questions
Calculate the number of moles of:
1) hydrogen molecules in  20g of hydrogen gas (H2)
2) hydrogen atoms in  20g of hydrogen gas (H2)

Please help me 😭🙏

Title: Re: Molar Mass
Post by: Hunter2 on November 27, 2024, 08:14:06 AM

1 mol hydrogen gas, it contains H2 molecules has a molar mass of about 2g/mol. Check the table of the periodic system of elements PSE.
The question ask how many mol you have if 20 g H2 is present.
And also how many mol of H atoms. One molecule contain two H atoms,

Title: Re: Molar Mass
Post by: TriVision on December 09, 2024, 11:33:57 AM

A mole is a measure of amount, like a dozen meaning twelve. When they ask for the number of moles in 20g of Hydrogen gas, you are supposed to convert the 20g of hydrogen to the number of molecules present (your teacher or the problem should provide it, otherwise a simple Google search would do) then convert that number to be represented by moles (which is (6.022 x 10^23 particles). In the second part, you need to double that answer, since it's just H2.