chem ch 6 and 7

energy

the capacity to do work

kinetic energy

E_k=1/2mv²

heat

transfer of thermal energy between two bodies

open system

can exchange mass and energy

closed system

can exchange energy but not mass

isolated system

cannot exchange energy or mass

state function

property that only depends on the initial and final states of a system

First law of thermodynamics

law of conservation of energy

components of internal energy

heat and work

work

w= change on volume x change in pressure

positive energy

entering system, heat absorbed, work done on system

negative energy

leaving system, heat released, work done by system

enthalpy

energy absorbed during a chemical reaction

endothermic

energy absorbed

exothermic

energy released

∆ h

Δ h products - Δ h reactants

standard enthalpy formation

energy absorbed during the formation of a compound from the element of which it is composed

∆ E (internal energy)

q + w OR ΔH - Δ(PV)

Hess’s Law

the change in enthalpy is the same whether the reaction takes place in one step or a series of steps

calorimetry

q = mc x Δ t

heat lost

-(heat gained)

specific heat

amount of heat required to raise the temperature of 1g of a substance by 1°C

specific heat of water

4.184 J/g°C

wavelength

distance between peaks

frequency

number of waves per second

amplitude

height of wave

quantum theory

atoms and molecules can only emit energy in particular packets of energy

E =

h µ

C =

λµ

Threshold energy

Φ

m_e=

9.11 × 10^-31 kg

c (speed of light)=

3.00 × 10⁸ m/s

h =

6.63×10^-34 Jxs

continuous spectrum

rainbow

line spectrum

light emissions only at certain wavelengths

particle-wave duality

Louis DeBogile- if light can act like waves and particles, so can electrons

λ=h/(mv)

Heisenburg uncertainty principle

it is impossible to know both momentum and position of a particle with complete certainty

(ΔxΔp ≥ h/4pi)

electron density

probability of finding an electron in a region of space

principal quantum number (n)

higher number means higher energy & further from nucleus

angular momentum quantum number (sub level, l)

“shape” of the region, s, p, d, f, corresponds to l= 0, 1, 2, 3; l goes from 0 to n-1

magnetic quantum number (orbital m_l)

parts of sub levels; s=1 p=3 d=5 f=7

electron spin quantum number (m_s)

2 electrons in each orbital

Pauli exclusion principle

electrons which share an orbital must have opposite spins

Hund’s rule

in a sublevel, no orbital may contain two electrons before all contain 1 electron

Newland’s law of octaves

properties repeat as a function of 8 elements

effective nuclear charge

the charge from the nucleus which applies to the valence electrons

Ionization energy (IE)

energy needed to remove an electron from an atom in the gaseous state

Electron Affinity (EA)

energy released when an atom in the gaseous state gains an electron