Enthalpy (Math)
A 250g copper pipe is heated from 10°C to 31°C. What is the energy needed to heat the pipe? The specific heat capacity of copper is .390 J/g-1°C-1.
2050 J or 2.050 KJ
What does the l value signify?
the angular momentum quantum number
- shape the orbital.
Which of the following has the smallest atomic radius?
Cl
F
N
Li
Ti
F
When do you use the Rydberg Equation?
Only with Hydrogen
The difference between kinetic and potential energy is that
(a) kinetic energy refers to energy stored within a substance and potential energy refers
to the possibility that a substance might release its energy
(b) kinetic energy refers to motion and potential energy refers to energy stored within a
substance
(c) kinetic energy refers the reaction of a substance experiencing a physical force and
potential energy refers to the possibility that a substance might release its energy
(d) kinetic energy refers the a change in the electron configuration of a substance and potential energy relates to the original electron configuration
(e) kinetic energy and potential energy represent two extremes: a substance has
potential energy at low temperature and kinetic energy at high temperature
B
The enthalpy change for the following reaction is 184.6 kJ. What is the standard enthalpy of formation, ΔHf, for HCl (g)?
2HCl (g) →H2 (g) + Cl2 (g)
-369.2 kJ
-184.6 kJ
-92.3 kJ
92.3 kJ
184.6 kJ
C
What are the quantum numbers for Helium?
n = 1
l = 0
ml = 0
ms = - 1/2
Which of the following is the least electronegative?
F
Fr
Cl
Mo
Pt
Fr
Using the Bohr model, determine the energy of an electron with n = 8 in a hydrogen atom.
−3.405 × 10−20 J
If work is done on a system is the w value positive or negative?
Positive
Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values:
N2H4(l) + H2(g) → 2NH3(g)
N2H4(l) + CH4O(l) → CH2O(g) + N2(g) + 3H2 (g) ΔH = -37 kJ
N2(g) + 3H2(g) → 2NH 3(g) ΔH = -46 kJ
CH4O(l) → CH2O(g) + H 2(g) ΔH = -65 kJ
-18 kJ
Which of the following is a correct set of quantum numbers for a 5f orbital?
(a) n = 5, l = 2, ml = +3
(b) n = 5, l = 4, ml = +3
(c) n = 3, l = 3, ml = +3
(d) n = 4, l = 3, ml = +2
(e) n = 5, l = 3, ml = +1
E
What is the correct order of increasing size of the following ions?
(a) P3– > Cl– > K+ > Ca2+
(b) Ca2+ > K+ > Cl– > P3–
(c) K+ > Cl– > Ca2+ > P3–
(d) K+ > Cl– > P3– > Ca2+
(e) None of the above is correct.
B
Using the Bohr model, determine the energy in joules of the photon produced when an electron in a Li2+ ion moves from the orbit with n = 2 to the orbit with n = 1.
1.471 × 10−17 J
What does a negative change in H value signify an endothermic or an exothermic reaction?
exothermic
A piece of metal weighing 59.047 g was heated to 100.0 °C and then put it into 100.0 mL of water (initially at 23.7 °C). The metal and water were allowed to come to an equilibrium temperature, determined to be 27.8 °C. Assuming no heat lost to the environment, calculate the specific heat of the metal.
Qwater= 1713.8 J
Cmetal= 0.402 J/g C
Write a set of quantum numbers for a 4f orbital
n = 4 l = 3 ml = 3, 2, 1, 0, -1, -2, -3
ms = +1/2. -1/2
What is the difference between ∆H and ∆H°?
(a) ∆H° is the temperature-dependent enthalpy change.
(b) ∆H° is the reference enthalpy change for a comparison reaction and ∆H is the enthalpy change of your reaction.
(c) ∆H is the reference enthalpy change for a comparison reaction and ∆H° is the enthalpy change of your reaction.
(d) ∆H° is the enthalpy change under the specific conditions of your reaction and ∆H is the enthalpy change at the standard state: 1 mol/L concentration, 1 ATM pressure, and typically 298.15 K.
(e) ∆H is the enthalpy change under the specific conditions of your reaction and ∆H° is the enthalpy change at the standard state: 1 mol/L concentration, 1 ATM pressure, and typically 298.15 K.
E
What is the energy (in joules) and the wavelength (in meters) of the line in the spectrum of hydrogen that represents the movement of an electron from Bohr orbit with n = 4 to the orbit with n = 6?
2.626×10−6 m 7.566×10−20 J
Is ΔH a state function?
No
A bomb calorimeter containing 900 grams of water was calibrated by burning a sample of benzoic acid (C6H5COOH), whose heat of combustion is –3227 kJ/mol. When 1.890 g of benzoic acid is burned in the calorimeter, the temperature of the water and the calorimeter increases by 8.32°C. Using these data, calculate the calorimeter constant for this calorimeter in J/℃.
Ccalorimeter = 2243 J/C
Which orbitals cannot exist?
2p 3p 4d 3f 6s 2d
3f and 2d
Rewrite the following list in order of decreasing electron affinity: fluorine (F), phosphorous (P), sulfur (S), boron (B).
Fluorine (F)>Sulfur (S)>Phosphorous (P)>Boron (B)
Light with a wavelength of 614.5 nm looks orange. What is the energy, in joules, per photon of this orange light? What is the energy in eV (1 eV = 1.602 × 10−19 J)?
3.233 × 10−19 J; 2.018 eV
What thermodynamic properties are state functions?
Enthalpy
Internal Energy
Pressure