Number of moles of glucose molecules

How many moles of glucose molecules are present in 1.8 grams of a sample of glucose?

Logic:

The molar mass, sometimes referred to as molecular weight, is the mass of one mole of a substance and is usually expressed in grams. 

Therefore, 

Therefore we can write,

What is the molar mass of glucose (C₆H₁₂O₆)? How to calculate....?

The molar mass of glucose can be calculated from the molar masses of individual atoms present in it.

From the molecular formula, C₆H₁₂O₆, one can find there are 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms in one molecule of glucose. 

We know that:

Molar mass of C = 12 g mol^-1

Molar mass of H = 1 g mol^-1 

Molar mass of O = 12 g mol^-1 

Therefore,

Molar mass of C₆H₁₂O₆=(6x12) + (12x1) + (6x16) = 72 + 12 + 96 = 180 g mol^-1

Answer:

Plugin the values to get the number of moles of glucose as follows: 

How to calculate the number of molecules?

It is also possible to get the number of molecules in the given sample by multiplying the number of moles with Avogadro number, N_A 

Thus, 

the number of molecules = n.N_A 

Where N_A = 6.022 x 10²³ 

In above glucose sample, 

the no. of glucose molecules = 0.01 x 6.022 x 10²³ = 6.022 x 10²¹ 

Remember that one mole of any substance contains Avogadro number of particles (may be atoms or molecules or ions etc.). If the substance is molecular, the number molecules will be equal to 6.022 x 10²³. If we take atomic substance, then the number of atoms in one mole is equal to Avogadro number.

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Related questions 

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