Thermochemistry

Question 1

What is the difference btwn. system and surroundings ?

Answer 1

The system is the matter that is being observed, and the surroundings is what surrounds that matter with an included boundary

Question 2

What are the different ways that a system can be characterized ?

Answer 2

Isolated: system cannot exchange energy (heat, work) or matter w/ surroundings
Closed: system can exchange energy but not matter w/ surroundings
Open: system can exchange both energy & matter w/ surroundings

Question 3

What factors are associated w/ isothermal processes?

Answer 3

• Temp is constant (implies internal energy of system is constant throughout process)
• Q=W

Question 4

When the thermal energy of the system is constant & there is no exchange btwn the system & environment is known as ?

Answer 4

Adiabatic processes

deltaU = -W (work done on the system)

Question 5

What are the standard conditions for measuring enthalpy, entropy, and Gibbs free energy ?

Answer 5

25C, 1atm, 1M

Question 6

When a solid turns directly into a gas & the vice versa happens are known as ?

Answer 6

Sublimation & deposition (respectively)

Question 7

The amount of energy required to raise the temp of 1g of a substance by 1 degree C (or 1 K) is known as ?

Answer 7

Specific heat

Question 8

Enthalpy changes of reactions are additive is an idea based on which law ?

Answer 8

Hess’s law (can also be expressed in bond dissociation energies)

Question 9

The 2nd law of thermodynamics states what ?

Answer 9

That energy spontaneously disperses from being localized to being spread out if not prevented from doing so