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.

6. what does the symbol ah stand for? o one calorie given off by a reaction the specific heat of a substance the heat capacity of a substance the heat of reaction for a chemical reaction

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

Jose and eric were given four samples in lab. the results of their analysis are shown in the table. based on the data they collected, which sample is most likely a metal?