AP Chemistry chapter 5 – Flashcards
Unlock all answers in this set
Unlock answersquestion
the following reaction is ___ and therefore heat is ___ by the reaction.
4 Al (s) + 3 O2 ? 2 Al2O3 (s) deltaH = -3351 kj
answer
exothermic, evolved
question
1 Joule =
answer
1 kg x m^2/s^2
question
the internal energy of a system is always increased by
answer
adding heat to the the system
question
When a system ____, deltaE is always negative
answer
gives off heat and does work
question
the energy chance in a system that occurs at constant pressure is ___, while the energy change in a system that occurs at constant volume.
a. deltaH, deltaE b. deltaE, deltaH
c. deltaH, qp d. delta H, deltaH
answer
a
question
what type of system can exchange energy with the surroundings but cannot exchange matter with the surroundings?
answer
closed
question
what sign is deltaH when a reaction is endothermic?
answer
positive
question
what is the sign of deltaH when heat is transferred from the surrounding to the system and work is done on the system?
answer
positive
question
what is the symbol for the change in internal energy?
answer
deltaE
question
what is the unit of enthalpy?
answer
J
question
Reaction 1: 2 H2 (g) + O2 (g) ? 2H2O (l) deltaH:-483.6 KJ
calculate the deltaH for Reaction 2: 4H2O (l)? 4H2 (g) + 2O2 (g)
answer
2 (483.6) = 967.2 KJ
question
Hess's law is a consequence of...
answer
enthalpy being state of function
question
The value of deltaH for the reaction below -186 kJ. Calculate the value of deltaHofformation (in kJ/mol) for HCL (g).
H2 (g) + Cl2 (g) ? 2HCl(g)
answer
-93.0
question
In most of its compounds, this element exists as a monatomic cation
a. O
b. Cl
c. Na
d. N
answer
c
question
which of the following elements may occur in the greatest number of different oxidation states?
a. C
b. F
c. O
d. Ca
answer
c
question
Isotope
answer
same number of protons, different number of neutrons
question
the name of the energy change when a gaseous atom, in the ground state, adds on electron
answer
electron affinity
question
The atomic numbers increase within a period, the atomic radius
answer
decreases
question
name an example of a reactive gas
answer
chlorine
question
Which of the following is an unreactive metal?
a. chlorine
b. gold
c. sodium
d. radon
answer
gold
question
the amount of energy absorbed or lost by a system as a energy is the form of heat during a process at constant pressure
answer
enthalpy change
question
the difference between the enthalpies of the products and reactants.
answer
delta H
question
Exothermic reaction, delta H is always
answer
negative
question
delta H is always positive for a ____ reaction
answer
endothermic
question
compounds whose enthalpies of formation are highly negative....
answer
are very stable
question
in an endothermic reaction, the total energy att he beginning of the reaction is...
answer
less than the total energy at the end of the reaction
