50 POINTS! Please answer these questions.

2 As (s) + 6 NaOH (aq) → 2 Na3AsO3 (s) + 3 H2 (g)

If 34.0g of As react with excess NaOH at STP, what volume of H2 will be produced in liters?

SnO2 (s) + 2 H2 (g) → Sn (s) + 2 H2O (l)

What mass of water is produce when 79.0g of SnO2 are consumed in the reaction above?

C3H8(g) + 5 O2 (g) → 3 CO2 (g)+ 4 H2O (g)

What volume of oxygen is required to completely combust 0.499L of propane (C3H8) at STP?