∆ is a symbol meaning "the change in"∆T = change in temperature (Kelvins, K)
The formula for kinetic energy is:
m = kg
v = m/s
1 mile is how many km?
1 pound is how many grams?
Expand these formulas for work.
m = mass in kg
g = gravity = 9.81 m * s ^-1
F = force in Newtons
w = work in joules
The formula for velocity.
v = sqaure root(2E/m)
m = meters
The ideal gas Law
PV = nRT
P = Atm
n = moles
R = 0.08206 for atm 8.314 for joules
T = temperature in Kelvins
kJ to Liter * atm
(0.101 kJ=1 L⋅atm)
p= liters * atm
v - change in volume (Liters)
Fahrenheit to Celsius
(1.8)C + 32 = F
What is the specific heat of water?
4.184 j/g ºCelsius
Grams to moles
Moles x Molecular weight = Grams
Calorimeter to q formula.
q reaction = -c (specific heat) calorimeter Δt
qreaction = -m water X 4.18 J/(g . °C) x Δt
Formulas for enthalpy.
–Enthalpy is a state variable
–ΔH = Hproducts – Hreactants
qreaction = ΔH = H products – H reactants
Rules of Thermochemistry
1. The magnitude of ΔH is directly proportional to the amount of reactant or product
2. ΔH for the reaction is equal in magnitude but opposite in sign for ΔH for the reverse of the reaction
3.The value of ΔH is the same whether the reaction occurs in one step or as a series of steps This rule is a direct consequence of the fact that ΔH is a state variableThis rule is a statement of Hess’s Law
The formula for enthalpies of formation.
–Enthalpies of Formation can be used to calculate ΔHfº for a reaction.
–To do this, apply this general rule:
–The standard enthalpy change, ΔHº, for a given thermochemical equation is equal to the sum of the standard enthalpies of formation of the product compounds minus the sum of the standard enthalpies of formation of the reactant compounds
ΔHº = ∑ΔHfº products - ∑ ΔHfº reactants
Note—elements can be omitted because ΔHfº = 0 for elementsΔH°f H+ (aq) = 0
Relationship between ΔH and ΔE
H = E + PV
ΔH = ΔE + Δ(PV)
Remember the Idea gas law
The PV product is important only where gases are involved; it is negligible when only liquids or solids are involved
Δ(PV) = ΔngRT
–Δng is the change in the number of moles of gas when the reaction takes place