Chemical Thermodynamics

Question 1

Sub-title? (General idea)

Answer 1

Heat of formation of MgO(s)

Question 2

What law do we use in this experiment

Answer 2

Hess’s Law!

Question 3

What is ***** Law say?

Answer 3

Delta H (enthalpy) for the overall reaction can be carried out and computed in steps

Question 4

Enthalpies are not state function. True/False?

Answer 4

False

Question 5

What’s a state function?

Answer 5

Do not depend on path taken (enthalpy)

Question 6

What reactions did we use to determine the heat of formation of MgO? (3)

Answer 6

1. H2+.5O2 H2O
2. Mg(s)+2HCL –> MgCl2 + H2
3. MgO(s) +2HCL –>MgCl2 +H2O
4. Mg(s) +.5O2 –> MgO

H4= H2-H3+H1

Question 7

Amanda put out a magnesium fire with water. Is Amanda still alive?

Answer 7

Nope

Question 8

If we lose heat to the surroundings in this a positive or negative error?

Answer 8

Negative

Question 9

Units for Delta H? Knowing these will help make the equations and math work

Answer 9

kcal/mole, J/mole, etc

Question 10

Why can’t you do this experiment in air in one step?

Answer 10

It lights on fire and you can’t stop the production of Mg3N2 when it burns in air

Question 11

All the delta H values are negative, meaning it is an _______ reaction

Answer 11

exothermic

Question 12

Why should you not put water on a magnesium fire?

Answer 12

It produces hydrogen gas which is flammable as well….

Question 13

Specific heats of metals are a ______ property.

Answer 13

intensive

Question 14

The law of dulling and pettit relates…

Answer 14

atomic mass and specific heat (roughly)