How many particles are there in 5.0 moles

3.01 × 10^24 particles

Explanation:

According to Avagadro, in one mole of a substance, there are 6.02 × 10^23 atoms or particles.

Using the formula: N = n × NA

Where;

N= number of particles or atoms

n = number of moles

NA = Avagadro's constant or number

This means that for 5 moles of a substance, there will be:

5 × 6.02 × 10^23

= 30.1 × 10^23

= 3.01 × 10^24 particles

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%