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Hw3 × Molecular w O Taylor Swift https. 41653 Convert mo How many G determine t

ID: 981124 • Letter: H

Question

Hw3 × Molecular w O Taylor Swift https. 41653 Convert mo How many G determine t . MInbox (16,87 G what is the G how manya + ii wwww.webassign.net/web/Student/Assignment-Responses/submit?dep-12881 136 c a how many atoms are in 14.2 He-) 3. +-1 points ZumChem8 3.CW.02. My Notes Question: 1 Consider samples of phosphine (PH3), water (H2O), hydrogen sulfide (H2S), and hydrogen fluoride (HF), each with a mass of 128 g. Rank the compounds from least to the greatest number of hydrogen atoms contained in the samples NOTE: Enter a subscript by surrounding it with underscore"" characters. For example H20 would be entered as H 2 O Submit Show Hints 8:22 PM 1/29/2016 Search the web and Windows

Explanation / Answer

Moles is directly proportional to number of atoms.

First we have to calculate the moles of each molecule.

PH3:

Moles of PH3 = mass / molar mass = 128 g/ 34 g/mol = 3.76

1mol of PH3 = 1 mol of P atoms + 3 mol of H atoms

So, 3.76 mol of PH3 = 3.76 x 3 mol of H atoms = 11.28 mol

Hence, 11.28 mol of H atoms are present in PH3.

H2O:

Moles of H2O = mass / molar mass = 128 g/ 18 g/mol = 7.1

1mol of H2O = 2 mol of H atoms + 1 mol of O atoms

So, 7.1 mol of H2S = 7.1 x 2 mol of H atoms = 14.2 mol

Hence, 14.2 mol of H atoms are present in H2O.

H2S:

Moles of H2S = mass / molar mass = 128 g/ 34 g/mol = 3.76

1mol of H2S = 2 mol of H atoms + 1 mol of S atoms

So, 3.76 mol of H2S = 3.76 x 2 mol of H atoms = 7.52 mol

Hence, 7.52 mol of H atoms are present in H2S.

HF:

Moles of HF = mass / molar mass = 128 g/ 40 g/mol = 3.2

1 mol of HF = 1 mol of H atoms + 1 mol of F atoms

So, 3.2 mol of HF = 3.2 x 1 mol of H atoms = 3.2 mol

Hence, 3.2 mol of H atoms are present in HF.

Moles is directly proportional to number of atoms.

Hence, Molecule with greater moles of H atoms has greater number of hydrogen atoms.

Therefore, order of hydrogen atoms present in the given samples is

HF < H2S < PH3 < H2O

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