How many atoms of hydrogen are in 0.75 mol of (c3h5)2s?

From the formula of the compound, we can see that there are 10 moles of hydrogen present in every mole of the compound. In the given amount:

Moles of hydrogen = 10 * 0.75
Moles of hydrogen = 7.5

Next, we know that each mole of a substance contains 6.02 x 10²³ particles. The atoms of hydrogen will be:
7.5 * 6.02 x 10²³ 

4.515 x 10²⁴ atoms of hydrogen will be present.