Question

How many molecules of glucose are present in 1.53 grams of glucose.

Answer 1

Hint: Number Of molecules of certain compounds can be calculated with the help of Avogadro number. Avogadro number means that one mole of any compound has $ 6.023 \times {10^{23}} $ molecules.

Complete step by step solution:
The mole consents as a bridge between the deep world of huge numbers of tiny molecules and being able to actually weigh substances out and work with them. A mole of a substance contains $ 6.023 \times {10^{23}} $ particles of that substance. This is Avogadro's number.
Now with the help of Avogadro no we will calculate the no of molecules.
First we will calculate the molar mass of glucose
The formula of glucose is $ {C_6}{H_{12}}{O_6} $
So its molar mass will be $ 6 \times 6 + 1 \times 12 + 16 \times 6 = 180 $
Now molar mass of glucose (or Any substance) means that 180 gm of glucose will required for 1 mole of glucose
Which mean in 180 gm of glucose there will be $ 6.023 \times {10^{23}} $ {as glucose has 180 molar mass}
 If 180 gm of glucose have $ 6.023 \times {10^{23}} $ molecules.
Therefore 1 gm of glucose will have $ \dfrac{{6.023 \times {{10}^{23}}}}{{180}} = 3.34 \times {10^{21}} $
Therefore 1.53 gm of glucose will have $ 3.3 \times {10^{21}} \times 1.53 = 5.049 \times {10^{21}} $ Molecules.

Note:
Chemists use molarity to measure the concentration of a solute in solution. Molarity $ \left( M \right) $ is the number of moles of solute in a liter of solution. Sodium chloride (NaCl) has a molecular mass of $ \left( {22.99 + 35.45} \right) = 58.44AMU $ , so if you dissolve 58.44 grams of table salt in a liter of water, you have a 1 $ \left( M \right) $ (1 molar) solution.