u1: calorimetry Flashcards
1
Q
∆Hr is
A
- the enthalpy change of the reaction
- difference between energy used to break bonds and energy released to reform bonds
2
Q
symbol for the enthalpy change during phase change
ΔH°vap
ΔH°cond
ΔH°melt
ΔH°fre
ΔH°boil
A
+
-
+
3
Q
enthalpy changes can be expressed in…
A
energy diagrams
4
Q
describe the following in regards to energy diagrams:
- horizontal lines
- vertical lines
- ΔH
and state how the arrow is formatted
A
- horizontal lines: initial and final states
- vertical lines: energy axis
- ΔH: diff. between two horizontal lines (initial v. final)
- arrow points at products/final states signifying direction of energy change
5
Q
determining experimental enthalpy formula
A
- ∆Hr = n∆H˚r
- ∆Hr: enthalpy under non-standard conditions, so more than 1 mole
- ∆H˚r: enthalpy under standard conditions, so 1 mole
6
Q
if more energy is added than released
A
∆Hsol’n is endothermic and +(kJ)
7
Q
if less energy is added than released
A
∆Hsol’n is exothermic and –(kJ)
