Heat and Enthalpy
If a system's internal energy increases by 250 kJ after the addition of 375 kJ of energy as heat, what was the value of work in the process?
-125 kJ
Arrange CsBr, NaCl, and RbBr in increasing magnitude of lattice energy
CsBr < RbBr < NaCl
All gases approach ideal behavior under conditions of ____ density and ____ temperature
low, high
A pair of isotopes has the same number of _____ and different number of _____
protons, neutrons
Which element has the highest electronegativity?
cesium, iodine, oxygen, lithium
oxygen
A piece of iron is heated to 95 degrees C and then placed in an insulated vessel containing 250. g of water at 25.0 degrees C. When the system come to equilibrium the temperature of the system is 35.0 degrees C. What is the mass (in g) of the iron?
Specific heat of iron - 0.450 J/g*K Specific heat of water - 4.184 J/g*K
387 g
What is the formal charge on the phosphorous atom in the phosphate ion?
0
What is the density of F2(g) at 1.00 atm and 25.0 degrees C?
1.55 g/L
How many neutrons are in 146C
8
Which ion has the largest radius?
Cl-, F-, K+, Cu2+
Cl-
Iron can be converted to Fe2O3 according to the reaction below. How much heat (in kJ) is required to convert 10.5 g of iron to Fe2O3?
2Fe + 3CO -> Fe2O3 + 3CO2 Delta H = 26.8 kJ
2.52 kJ
Which molecule contains a carbon which a negative formal charge?
CO, CO2, H2CO, CH4
CO
A 14.0 g sample of N2(g) occupies what volume at 0 degrees C and 1.00 atm?
11.2 L
Which ion has 26 electrons?
Cr2+,Fe2+,Ni2+, Cu2+
Ni2+
Which ion is the smallest?
Al3+, Na+, F-, O2-
Al3+
What is the standard enthalpy of formation of NH3?
4NH3 + 5O2 -> 4NO + 6H2O Delta H = -904.8 kJ/mol
Delta H NO = 90.3 kJ/mol Delta H H2O = -241.8
-46.1 kJ/mol
A central atom has two lone pairs and three single bonds. What is the molecular geometry?
T-shaped
What volume of oxygen gas, measured at 27 degrees C and 0.987 atm, is produced from the decomposition of 67.5 g of HgO?
2HgO -> 2Hg + O2
Molar Mass of HgO = 216.59 g/mol
3.89 L
Lithium has two naturally occurring isotopes, 6Li and 7Li, with masses 6.015 amu and 7.016 amu respectively. What is the relative abundance of each isotope?
6Li = 7.49%
7Li = 92.51%
Which element is more electronegative than arsenic and less electronegative than sulfur?
Chlorine, phosphorous, tin, oxygen
phosphorous
What is the delta H for this reaction?
3H2 + O3 -> 3H2O
Delta H H2 + 1/2 O2 -> H2O = -286 kJ/mol Delta H 3O2 -> 2O3 = 271 kJ/mol
-994 kJ/mol
Which molecule has a 120 bond angle?
CO2, NH3, IF3, SO3
SO3
A mixture of 3.25 moles of oxygen gas and 2.75 moles of nitrogen gas exert a total pressure of 22.4 atm. What is the partial pressure of oxygen?
12.1 atm
Two isotopes of hypothetical element X exist with abundances of 30.00% 100X and 70.00% 101X. What is the appropriate atomic mass of X (in amu)?
100.7 amu
Is it harder to remove an electron from the s subshell or the p subshell of the same energy level?
s subshell