Check my answers ? 1. which of the following is a correctly written thermochemical equation? nh4cl nh4+ + cl 2c8h18 + 25o2 16co2 + 18h2o, h = 5,471 kj/mol fe (s) + o2 (g) fe2o3 (s), h = 3,926 kj --> c3h8 (g) + 5o2 (g) 3co2 (g) + 4h2o (l), h = 2,220 kj/mol 2. how does a phase change affect a thermochemical equation? it alters the moles of reactants. --> it can affect the (delta) h value. it alters the products. it affects the balance of the equation. 3. for the reaction ch4 (g) + 2o2 (g) co2 (g) + 2h2o (l), h = 890 kj, what will be the change in enthalpy when 3 moles of methane react in excess oxygen?
890 kj
--> 2.67 × 103 kj
+890 kj
+2.67 × 103 kj
4. in which of the following thermochemical equations would the h be considered a heat of solution?
nh4cl (s) nh4+ (aq) + cl (aq), h = + 14.8 kj/mol
2c8h18 (l) + 25o2 (g) 16co2 (g) + 18h2o (l), h = 5,471 kj/mol
--> 4fe (s) + 3o2 (g) 2fe2o3 (s), h = 3,926 kj
c3h8 (g) + 5o2 (g) 3co2 (g) + 4h2o (l), h = 2,220 kj/mol
5. for the following reaction at stp, how much heat will be required to produce 63 l of no? (at stp, one mole of any gas occupies 22.4 l.)
n2 (g) + o2 (g) 2no (g), h = 180.5 kj
+63 kj
+127 kj
--> +254 kj
+508 kj