AP Chem Test 4

Question 1

Hess’s Law of Summation

Answer 1

Hess’s law of summation: A series of chemical reactions can be added together to form a new chemical reaction. The sum of individual energies will be the total energy of the new reaction.

We algebraically manipulate equations to add to a new equation and we can add the energies

Reversing an equation will reverse the sign of enthalpy

Multiplying by a constant will also multiply the energy by the same constant

Find a unique compound in each equation you must add which indicates how you need to manipulate that equation.

Question 2

Formation Reactions

Answer 2

FORMATION REACTIONS: a formation reaction forms one mole of product from elements in their free and natural state. Example: formation of ammonia

Question 3

For thermodynamic data: standard state

Answer 3

For thermodynamic data: standard state

25C (room temperature)

1 atm

1 M