1. CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
Chemistry 120 Sp2015 Quiz 9 - Key
Magnesium ions can be precipitated from seawater by the addition of sodium hydroxide. How much sodium hydroxide in grams must be added to a sample of seawater to completely precipitate the 88.4 mg of magnesium present?
Mg2+ + 2NaOH  Mg(OH)2 + 2Na+
88.4mg Mg2+ x (1 g/1000mg) x (1 mol Mg2+/24.31g) x (2 mol NaOH/1 mol Mg2+) x (40.00g NaOH/1 mol) = g of NaOH
How much heat is produced by the complete combustion of 273 g of methane?
CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
ΔH°rxn = kJ
273g of CH4 x (1 mol CH4/16.05 g) x (-802.3kJ/1 mol CH4) = 1.36 x 104 kJ