EXAM 1 (Ch 1-3)
Convert 200 kg to lb (1lb = 453.59 g)
441 lb
what is the name of this compound: CuClO4
copper (I) perchlorate
Is CFCl3 a polar molecule?
yes
What volume would 3.51 moles of CO2 gas occupy under STP?
78.6 L
What volume of 0.500 M hydrochloric acid
solution needs to be added to excess sodium
carbonate in order to cause the evolution of 14.5 L
of carbon dioxide gas at STP?
2HCl(aq) + Na2CO3(aq) → 2NaCl(aq) + H2O(l) + CO2(g)
2.59 L of HCl solution
calculate the abundance of thallium isotopes 203Ta (202.97) and 205Ta (204.97) The atomic mass of antimony is 204.38. Report abundance to 3 sig figs.
203Ta= 29.5% and 205Ta= 70.5%
Sodium Carbonate has a chemical formula of ____ . Molar mass = ____ g/mol.
a. how many moles of this compound in in 902 g
b. how many moles of carbonate ions are in 38.2 g of this compound?
c. what is the mass of sodium contained in 38.2g of this compound?
d. what is the percent composition of oxygen in this compound?
Na2CO3, 105.81 g/mol
a. 8.53 mol Na2CO3
b. 0.361 mol CO32-
c. 16.5 g Na
d. 45.4% O
CH 7 practice problems pg3
CH 7 practice problems pg3 answers
At what temperature would 0.345 moles of H2 gas occupy 1.50 L at 790. mmHg?
55 K
What is the condensed electron configuration of cobalt ion, Co3+ ?
[Ar] 4s0 3d6
How many formula units are in 3.78 g of NaNO3?
2.68 x 1023 formula units
a. draw the lewis dot structure of O3
b. draw all if any resonance structures for the compound
c. calculate the formal charge of each atom in the structure
CH 4.2 Key Q#11
Write the balanced reaction equation that occurs between NaCl and Pb(NO3)2
a. molecular eq?
b. total ionic eq?
c. net ionic eq?
CH 8 pp #2 answers
If the volume of H2 gas (1.5 L ), (55 K) is reduced to 0.950 L at constant pressure, what is the temperature of the gas?
34.8 K
calculate the total energy delivered by a 0.072 mol burst of UV light (wavelength= 125 nm)
6.90 x 104 J or 6.90 kJ
calculate the energy of a photon with a wavelength of 8.08 nm
2.46 x 10-17 J
BrF5
a. central atom?
b. # of electron domains?
c. electron geometry?
d. molecular shape?
e. F–Br–F bond angle?
f. Hybridization
g. Orbitals used in Br–F bond
h. # of sigma bonds
i. # of pi bonds
a. Br
b. 6
c. octahedral
d. square pyramidal
e. < 90 degrees
f. sp3d2
g. sp3d2 + p
h. 5
i. 0
NiO2 + 2H2O + Fe → Ni(OH)2 + Fe(OH)2
a. what is oxidized?
b. what is reduced?
a. Fe
b. Ni
What is the mole fraction of each gases (CO2, 3.51 mol, H2, 0.345 mol, SO2, 0.0215 mol, N2, 1.11 mol ) if the gas samples are combined into a single 1L flask?
1. 0.703
2. 0.0691
3. 0.00431
4. 0.222
Ammonium nitrate can decompose explosively
when heated according to the equation:
2NH4NO3(s) → 2N2(g) + 4H2O(g) + O2(g)
How many liters of gas would be formed at 450 °C
and 2.00 atm pressure by explosion of 450 grams
of NH4NO3?
584 L
Will the photoelectric effect occur when x-ray light (v=9.99 x 1017 Hz) hits cobalt metal (phi = 8.01 x 10-19)? If yes, what is the kinetic energy of the photoelectron ejected?
Ephoton= 6.62 x 10-16 J > 8.01 x 10-19 so photoelectric effect will occur. KE= 6.61 x 10-16 J
show Q13 on 3 practice test
A. principal quantum number, n?
B. angular momentum quantum number, l?
A. 3
B. 2
What is the enthalpy of formation of NO2 (ΔH of f) if the enthalpy change of the following reaction (ΔH rxn) is 67.8 kJ?
N2 (g) + 2O2 (g) ⟶ 2NO2 (g)
33.9 kJ
Rank the four gases (CO2, H2, SO2, N2) in order of increasing velocity
SO2, CO2, N2, H2
What is the heat (in kJ) being exchanged by the system when the thermometer in a 15.0g reaction solution in a coffee cup calorimeter reads a 45.2 °C increase in temperature? The specific heat of water is 4.186 J•g •°C-1.
-2.84 kJ