Exam 1
These elements are located in group 8A of the periodic table and are mostly colorless, odorless, and unreactive/inert.
Noble Gases
What is the mass in grams of 7.24 moles of Ag3PO4?
3,030g Ag3PO4
How much energy is required to heat up 80 g of water from 26C to 48C? Give your answer in J.
7.4 x 103 J
Fr = 1 valence electron
At = 7 valence electrons
Write both A/Z and symbol-mass formats for the following atoms:
a) Hg - 80 electrons, 80 protons, 121 neutrons
b) Pt - 78 electrons, 78 protons, 117 neutrons
c) Br - 35 electrons, 35 protons, 45 neutrons
a) 20180Hg and Hg-201
b) 19578Pt and Pt-195
c) 8035Br and Br-80
Hydrogen sulfide gas burns in oxygen to produce sulfur dioxide and water vapor.
2H2S(g)+3O2(g)→2SO2(g)+2H2O(g)
What mass of oxygen gas is consumed in a reaction that produces 4.60mol SO2?
221g O2
What mass (in grams) of Mg(NO3)2 is present in 145 mL of a 0.150 M solution of Mg(NO3)2?
3.23g Mg(NO3)2
Calculate the wavelength of light that corresponds to a frequency of 8.01 x 1014 per second. Report your answer in units of nanometers
374nm
The density of mercury is 13.6 g/mL. What is the mass in kilograms of a 2.00 L commercial flask of mercury?
27.2 kg Hg
Given the balanced equation:
3CuS + 8HNO3 → 3Cu(NO3)2 + 3S + 2NO + 4H2O What number of molecules of Cu(NO3)2 is produced when 67g of HNO3 is consumed?
2.40 x 1023 molecules Cu(NO3)2
96.0 g of a gas occupies 48.0 L at 700.0 mm Hg and 20.0 °C. What is its molecular weight?
52.2 g/mol
What is the wavelength (in nm) of a photon that has an energy of 4.31 x 10-19 J?
461nm
The mass of a 5.00 grain aspirin tablet to milligrams (1 grain = 0.00229oz) (1oz = 28.35g)
325mg
Provide the molecular, complete ionic, and net ionic equations for the reaction between aqueous SrBr2 and aqueous K2SO4
Molecular: SrBr2(aq) + K2SO4(aq) --> SrSO4(s) + 2KBr(aq)
Total Ionic: Sr2+(aq) + 2Br-(aq) + 2K+(aq) + SO42-(aq) --> SrSO4(s) + 2K+ (aq) + 2Br-(aq)
Net Ionic: Sr2+(aq) + SO42-(aq) --> SrSO4(s)
A 2.00 g sample of ammonia reacts with 4.00 g of oxygen according to the equation
4NH3+5O2→4NO+6H2O
How much excess reactant (in grams) remains after the reaction has stopped?
0.297g excess NH3 remains
Use an orbital diagram to describe the valence shell and determine the number of unpaired electrons for the following atoms: Si, Te, N
Show orbital diagrams on multiuser whiteboard
Si: 2 unpaired valence electrons
Te: 2 unpaired valence electrons
N: 3 unpaired valence electrons
Calculate the elemental atomic mass of Mg if the naturally occurring isotopes are 24Mg, 25Mg and 26Mg. Their masses and abundances are as follows:
24Mg: 23.98504amu, 78.70%
25Mg: 24.98584amu, 10.13%
26Mg 25.98259amu, 11.17%
24.31amu
The nickel-cadmium (nicad) battery, a rechargeable “dry cell” used in battery-operated devices, uses the following redox reaction to generate electricity:
Cd(s) + NiO2(s) + 2H2O(l) → Cd(OH)2(s) + Ni(OH)2(s)
Identify the substances that are oxidized and reduced, and indicate which is the oxidizing agent and which is the reducing agent.
Cd(s) oxidized, reducing agent
NiO2(s) reduced, oxidizing agent
500.0 liters of a gas in a flexible-walled container are prepared at 700.0 mmHg and 200.0 °C. The gas is placed into a tank under high pressure. When the tank cools to 20.0 °C, the pressure of the gas is 30.0 atm. What is the volume of the gas?
According to the Combined Gas Law, 9.51 L
Calculate the effective nuclear charge experienced by a valence p-electron in boron and a 2p electron in Fluorine? (Give answer to three sig figs)
Zeff(Fluorine) = 5.20