Question

18
Calculate number of moles in:
18
Calculate number of moles in:

18
Calculate number of moles in:
(a) 2g Hydrogen molecules​

Answer 1

Answer:

atomic mass of hydrogen is 2 and 1mole gm is atomic mass

so there are 4 moles of hydrogen molecules

Answer 2

answer;

Number of moles = 0.1 mole

Number of molecules = 6.022 × 10²² molecules

Total number of atoms = 1.44528 × 10²⁴ atoms

Explanation:

The chemical formula of glucose is C₆H₁₂O₆

We know that,

Mass of 1 C-atom = 12g

Mass of 1 H-atom = 1g

Mass of 1 O-atom = 16g

Hence,

Molar mass of glucose

= Mass of 6 C-atoms + Mass of 12 H-atoms + Mass of 6 O-atoms

= (12×6) + (1×12) + (16×6)

= 72 + 12 + 96

= 180g

Given mass = 18g

We know that,

Number of moles = Given mass / Molar mass

Substituting the values we get,

Number of moles = 18 / 180

Number of moles = 1 / 10

Number of moles = 0.1 mole

We also know that,

Number of moles = Number of molecules / Avogadro number

Number of molecules = Number of moles × Avogadro number

Number of molecules = 0.1 × 6.022 × 10²³

Number of molecules = 6.022 × 10²²

We know that,

1 molecule of glucose contain 6 C-atom, 12 H-atom and 6 O-atoms

Hence,

total atoms in 1 molecule = 6 + 12+ 6

                                         = 24 atoms

Therefore,

Total number of atoms in 18g glucose = 24 × 6.022 × 10²²

                                                               = 144.528 × 10²²

                                                               = 1.44528 × 10²⁴

1 mole of hydrogen contain = 2×1

= 2g

2g of h2 contain = 2/2 × avogadro no.

2/2= 1

1×6.022×10²³= 6.022×10²³ - Anwer

hope it helps