Question

What is the molar mass and the mass of $5.0$ mol of acetylsalicylic acid, ${C_9}{H_8}{O_4}$ ?

Answer 1

Hint : The molar mass is calculated by dividing the mass of a given chemical element or chemical compound (in grams) by the amount of material (in moles). By adding the standard atomic masses (in $g$ / $mol$ ) of the constituent atoms, the molar mass of a substance can be measured.

Complete Step By Step Answer:
Acetylsalicylic acid commonly known as Aspirin, is a nonsteroidal anti-inflammatory drug that is taken orally. Aspirin degrades quickly in solutions of ammonium acetate or alkali metal acetates, carbonates, citrates, or hydroxides. It is soluble in dry air but eventually hydrolysis to acetic and salicylic acids when exposed to moisture. This substance is analgesic, antipyretic, and anticoagulant.
The molecular weight of acetylsalicylic acid is $180.16$ $amu$ . So, the molar mass of acetylsalicylic acid is $180.16$ $g \cdot mo{l^{ - 1}}$ . One molecule of acetylsalicylic acid is made up of $9$ atoms of carbon, $8$ atoms of hydrogen and $4$ atoms of hydrogen.
We know that the mass of one mole of acetylsalicylic acid is $180.16$ $g \cdot mo{l^{ - 1}}$ . We need to find out the mass of $5.0$ moles of acetylsalicylic acid. This is given by multiplying the molar mass of acetylsalicylic acid into $5$ . So, the mass of $5.0$ moles of acetylsalicylic acid is given by:
$5 \cdot mol \times 180.16 \cdot g \cdot mo{l^{ - 1}} = 5 \times 180.16g$
$= 900.8g$
Thus, the molar mass acetylsalicylic acid, ${C_9}{H_8}{O_4}$ or aspirin is $180.16$ $g \cdot mo{l^{ - 1}}$ .
The mass of $5.0$ moles of acetylsalicylic acid, ${C_9}{H_8}{O_4}$ is $900.8g$ .

Note :
It must be noted that, usually the molar mass is represented by the unit $g \cdot mo{l^{ - 1}}$ but in the answer which is the mass of $5$ moles, the result is in grams. This is because when the molar mass is multiplied with the number of moles, the unit mol gets cancelled. This results in the answer being measured in grams.