Section: 6.1

20) Calculate the number of moles of aspirin, C9H8O4, in a 4.0 gram tablet.

A) 2.2 x 10-4 ċ 9 H:8 0.4

B) 2.2

C 12.61 H 1.01 16.00

C) 4.6 x 10-3

9x612.01) + 8x (1.01) + 4 (16.00) - 180.17

D) 0.022

4.0 X (180.17) = 720

D = 0.022 moles

Explanation:

Given dа ta:

Mass of aspirin = 4.0 g

Number of moles = ?

Solution:

First of all we will calculate the molar mass of aspirin.

Molar mass of aspirin = 12*9 + 1*8 + 16 * 4

Molar mass of aspirin = 108 + 8 + 64

Molar mass of aspirin = 180 g/mol

Number of moles = mass/molar mass

Number of moles = 4.0 g / 180 g/mol

Number of moles = 0.022 mole