How many grams are in 2.54 x 10^23 molecules of CO2

= 0.42 moles of CO2

Explanation:

From Avogadro's constant

6.02×10^23 molecules are in 1 mole of CO2

2.54×10^23 molecules will be in

=[(2.54×10^23) ÷ (6.02×10^23)]

= 0.42 moles of CO2

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%

um i think it might be a car?