Question

Glucose has a gram molecular mass of:
(A)$180 \cdot 096u$
(B) $180 \cdot 096g$
(C) $180 \cdot 0096u$
D) $18 \cdot 0096g$

Answer 1

Gram molecular mass is defined as the sum of the masses of all the atoms present in one molecule of a compound. Glucose is a simple six carbon sugar. It is the most abundant monosaccharide found in the living world and is the main product of photosynthesis.

Complete step by step answer:
Step 1: Consider the molecular formula of glucose, to find the elements involved in the formation of one molecule of Glucose.
The molecular formula of glucose $= {{\text{C}}_6}{H_{12}}{O_6}$
Step 2: Find the atomic mass of each element present in the molecule.
Atomic mass of Carbon (C) $= 12 \cdot 01g$
Atomic mass of Hydrogen (H) $= 1 \cdot 008g$
Atomic mass of Oxygen (0)$= 16 \cdot 00g$
Step 3: Calculate the total mass of each element present in the molecule.
From the molecular formula of glucose, we find that there are six atoms of carbon, twelve atoms of hydrogen and six atoms of oxygen in one molecule of glucose. Considering this data, we can find:
Total mass of carbon (C) in a molecule glucose will be,$\left( {12 \cdot 08 \times 6} \right)g = 72 \cdot 06g$
Total mass of Hydrogen(H) in a molecule glucose will be,$\left( {1.008 \times 12} \right)g = 12 \cdot 096g$
Total mass of Oxygen (O) in a molecule of glucose will be, $\left( {16 \cdot 00 \times 6} \right)g = 96.00g$
Step 4: Obtain the molecular mass of glucose by adding up the total mass of the individual element.
Therefore, the gram molecular mass of Glucose will be:
$\left( {72 \cdot 06 + 12 \cdot 096 + 96 \cdot 00} \right)g = 180 \cdot 096g$
From the above calculations we can conclude that, Option B is the correct choice.

Note:
Even though the numeric value of molecular mass and gram molecular mass is the same, there is a slight difference between the two. Whenever we refer molecular mass of a compound, we indicate the mass of one molecule of the compound relative to the mass of one C-12 atom and it is represented in atomic mass units (a.m.u.) but when we refer gram molecular mass, we indicate the mass of one mole of the compound in grams.