Question

how many molecules are there is 25 grams of glucose

Answer 1

Explanation:

1 mole molecules = 6.022×10^23 molecules

First calculate moles of glucose. Then convert moles to molecules.

Calculate the number of moles (n) of C6H12O6 in 26.4 g.

n = m/M, where;

n = mole(s) = ?

m = mass(g) = 26.4 g C6H12O6

M = molar mass(g/mol) C6H12O6 = (6 × 12.011 g/mol C) + (12 × 1.008 g/mol H) + (6 × 15.999 g/mol O) = 180.16 g/mol

n C6H12O6 = 26.4 g C6H12O6/180.16 g/mol = 0.1465 mol C6H12O6

Use dimensional analysis to convert moles to molecules.

0.1465 mol C6H12O6 × 6.022×10^23 molecules/mol = 8.82×10^22 molecules C6H12O6 to three significant figures

We can put both steps into one equation.

26.4 g C6H12O6 × 1 mol C6H12O6/180.16 g C6H12O6 × 6.022×10^23 molecules C6H12O6/1 mol C6H12O6 = 8.82×10^22 molecules C6H12O6 to three significant figures

Note: 26.4 g/180.16 g/mol is the same as 26.4 g × 1 mol/180.16 g. It is the same as dividing a fraction (g/mol) by multiplying by its reciprocal (mol/g).

There are ~8.82×10^22 molecules of glucose in 26.4 g.