Question

Calculate the mass of solid sodium that's needed to fully react with 4.0 L of chlorine gas at STP.

_Na ₍s₎+_Cl₂₍g₎ →_NaCl₍aq₎

Answer 1

Answer: 8.28g Na

Explanation: use ideal gas law

PV= nRT

Solve for moles of Cl2

n= PV/ RT

Substitute:

= 1 atm x 4.0 L / 0.08205 L.atm/ mol. K x 273 K

= 0.18 moles Cl2

Do stoichiometry to solve for m of Na

2 Na + Cl2 => 2 NaCl2

=0.18 moles Cl2 x 2 mol Na/ 1 mol Cl2 x 23g Na / 1 mol Na

= 8.28 g Na.