To find the number of molecules in a given mass of a substance, you can use the following steps:
1. Determine the molar mass of the substance (H2SO4 in this case).
2. Calculate the number of moles using the formula: Moles = Mass (grams) / Molar mass.
3. Use Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol, to find the number of molecules.
For sulfuric acid (H2SO4):
1. Molar mass of H2SO4 = 2(1.01 g/mol) + 32.07 g/mol + 4(16.00 g/mol) = 98.09 g/mol
2. Moles of H2SO4 = 49 g / 98.09 g/mol ≈ 0.499 moles
3. Number of molecules = Moles x Avogadro's number
Number of molecules = 0.499 moles x 6.022 x 10^23 molecules/mol ≈ 3.00 x 10^23 molecules
So, there are approximately 3.00 x 10^23 molecules of H2SO4 in a 49g sample.