density of gas
: p x MM(g/mol) / R x T
Partial Pressures
p(x) = n(x) x [RT/V]
p(tot)= p(x) + p(y) + p(z) or [n(x)+n(y)+n(z)]* RT/V
molar fraction (x)
: n(a) / n(tot)
p(x) partial = molar fraction x p(tot)
*molar fractions of a component is equivalent to its percent by volume divided by 100, so 78% N
2
=
0.78atm
*when finding p,v,n,or t of a component, use p(tot) to find its partial pressure
Grahams law of effusion
:
rate(a)/ rate(b)= root[MM(b)/MM(a)]
Energy and specific heat
heat gained or lost(q) + final energy (w) gained or lost = E(j)
q(j)= C x T(°C), C = j/°C
when given mass: q(j)= m(g) * C
s
(j/g°C) * ΔT(°C)
Thermal Equilibrium
q(metal)= - q(water)
w= - P ΔV, use E - q to find w
Reactions at constant volume:
ΔErxn= q
v
,w = 0 at constant volume
*
used in bomb calorimetry,
where q(cal) depends on T
q(cal)= C(cal)ΔT
q(cal)= - qrxn and qrxn= qv which
= ΔE
rxn
Heat at constant pressure (enthalpy)
H = E + PV
Change in enthalpy
: ΔH = ΔE + P ΔV
* use (q
p
+ w) and w= P ΔV, therefore ΔH = q
p
- (coffee cup calorimetry)
q(soln)= M x C
s
x ΔT, q
rxn
= - q(soln) and q
rxn
/mol = ΔH
rxn
Relationships involving ΔH
rxn
1. If a chemical equation in multiplied by some factor,
ΔH
rxn
is multiplied by that factor

2. If a chemical equation is reversed, ΔH
rxn
changes signs
3. If a chemical equation can be expressed as the sum of a series of steps, delta ΔH
rxn
for the overall
equation is the sum of the heats of reactions for each step
* algebraically solve for any delta ΔH using
ΔH
3
= ΔH
1
+ ΔH
2
Enthalpies of reaction
1. standard state
2. ΔH°: standard enthalpy change
3. ΔH°
f
: standard enthalpy of formation
*Use standard states and delta ΔH° to find delta ΔH°
f
- this will occur in a chemical equation where 1 product is formed
ΔH°
rxn
= Δ
Ʃ
H°
f
(products) - Δ
Ʃ
H°
f
(reactants)
v(1/s) = c(m/s)/ λ(m)
interference
: EM waves interact cancel each other out
constructive interference
: waves align with overlapping crest, resulting in x2 amplitude
destructive interference

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- Spring '10
- Price
- Chemistry, Atom, Electron, Partial Pressure, Ion, Chemical bond