[aml6492]

1) What mass of Cu2S can be produced from the reaction of 100g copper with 50 g of sulfur?

2) If mole fraction = moles x/ total # of moles, What is the mole fraction of a 10% by weight solution of CH₃OH in water?

3) Given that the density of 10.0% aqueous NaCl is 1.071 g/cm³, what is the molar concentrations of Na and Cl?

4) What is the molarity of a solution containing 314 g of KCl(s) in 1000g of water
 dH2O = 1.00 g/cm³

[ARGOS++]

Dear aml6492;

And your Answers/Assumptions are: ?,   ─    And would you please read:  "Forum Rules" (4.)

For your first question:
That’s a normal "Stoichiometry Problem".
So you may apply the recipe/scheme from the Topic "Stoichiometry Problem":   "Stoichiometry Problem (#23'025)"
Therein is also an Example Diagram: How to do a "Stoichiometry Problem".

Good Luck!
                    ARGOS⁺⁺