What is the standard heat of reaction for the formation of NO2(g) from NO(g) and O2(g)? Write the balanced equation first. You can find the standard heats of formation in table 17.4 of your book on page 580. (Show all work including the equation you use to solve). (5 points). See page 581 for an example.

The answer to your question is ΔHf = -114.2 kJ/mol

Explanation:

Balanced chemical reaction

                2NO(g)  +  O₂(g)   ⇒   2NO₂(g)

Standard heat of formation

ΔHf NO (g) = 90.3 kJ/mol

ΔHf O₂ (g) = 0.0 kJ/mol

ΔHf NO₂ (g) = 33.2 kJ/mol

- For this reaction

ΔHf = ∑ΔHf products - ∑Hf reactants

-Substitution

ΔHf = 2(33.2) - 2(90.3) - 0

-Simplification

ΔHf = 66.4 - 180.6

-Result

ΔHf = -114.2 kJ/mol

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.