221k views
3 votes
Calculate the number of moles of the following:

188.0 g Zn
24.2 L of CH4 at STP
1.4 x 1023 molecules of C6H1206


1 Answer

1 vote

Answer:

Number of moles of Zn = 2.88 mol

Number of moles CH₄ = 1.08 mol

0.232 mole of C₆H₁₂O₆

Step-by-step explanation:

Given data:

Mass of Zn = 188.0 g

Number of moles of Zn = ?

Solution:

Number of moles = mass / molar mass

Number of moles = 188.0 g / 65.38 g/mol

Number of moles = 2.88 mol

24.2 L of CH₄ at STP.

PV = nRT

n = PV/RT

n = 1 atm . 24.2 L / 0.0821 atm. L. mol⁻¹ . K⁻¹ × 273.15 K.

n = 1 atm . 24.2 L / 22.43 atm. L. mol⁻¹

n = 1.08 mol

1.4 ×10³ molecules of C₆H₁₂O₆

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 1.4 ×10²³ molecules of C₆H₁₂O₆

1 mole = 6.022 × 10²³ molecules

(1 mole/6.022 × 10²³ molecules) × 1.4 ×10²³ molecules

0.232 mole of C₆H₁₂O₆

User Potasmic
by
5.6k points