Redox
Aqeuous Rxn
Thermodynamics
Gases
100
What happens to the electrons of an element when it's being oxidized vs reduced?
Oxidized - loses electrons
Reduced - gains electrons
100
A teaspoon of table sugar contains about 0.01 mol sucrose. What is the molarity of sucrose if a teaspoon of sugar has been dissolved in a cup of tea with a volume of 200 mL?
0.05 M
100
A flask containing 8.0 × 102 g of water is heated, and the temperature of the water increases from 21°C to 85°C. How much heat did the water absorb?
(The specific heat of water is 4.184 J/g °C)
2.1 × 102 J
100
Convert 742 torr to atm.
1 atm = 760 torr
742 torr = 0.976 atm
200
Write the net ionic equation for the following reaction:
2KI(aq) + Pb(NO3)2(aq) --> PbI2(s) + 2KNO3(aq)
Pb2+(aq) + 2I-(aq) --> PbI2(s)
200
When aqueous solutions of Ba(NO3)2 and (NH4)3PO4 are mixed, the products are what types of electrolytes?
One strong electrolyte and one non-electrolyte.
200
49 kJ
200
The gas in the can is initially at 24°C and 360 kPa, and the can has a volume of 350 mL. If the can is left in a car that reaches 50°C on a hot day, what is the new pressure in the can?
390 kPa (P/T = const.)
300
What is the oxidizing agent for this reaction?
2NH3 + 3CuO --> 3Cu + N2 + 3H2O
CuO
300
According to the EPA, when the concentration of lead in tap water reaches 15 ppb, certain remedial actions must be taken. At this concentration, what mass of lead (μg) would be contained in a typical glass of water (300 mL)?
(ppb - parts per billion; (mass solute/mass solution) x E9)
4.5μg
300
When 2.50 g of methane burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion per mole of methane under these conditions?
–802 kJ/mol
300
A 5.73-L flask at 25°C contains 0.0388 mol of N2, 0.147 mol of CO, and 0.0803 mol of H2. What is the total pressure in the flask in atmospheres?
1.137 atm
400
Identify the oxidizing and reducing agents for the following reaction:
Sn(s) + 2HCl(g) --> SnCl2(s) + H2(g)
oxidizing agent: HCl
reducing agent: Sn
400
Indicate which direction (right, left, or NR) the reaction proceeds and identify the type of the reaction (ppt, gas, redox, neutralization, combustion, or none).
a) 2AgNO3 + Zn _____ Zn(NO3)2 + 2Ag
b) 2KOH + (NH4)2SO4 ____ K2SO4 + 2H2O + 2NH3
c) Mg(NO3)2 + Cu ____ Mg + Cu(NO3)2
a) right, redox
b) right, gas
c) left, redox
400
A 95.0g sample of a metal is heated to 98.0°C, then placed into 150.0g of water initially at 23.0°C in a calorimeter. The final temperature of the water is 26.4°C. What is the identity of the metal? The specific heat of water is 4.184 J/g °C.
Tin
400
A sample of carbon dioxide occupies 0.300 L at 10 °C and 750 torr. What volume will the gas have at 30 °C and 750 torr?
0.321 L (V/T = const.)
500
Predict the result of mixing reasonably concentrated solutions of lead nitrate and ammonium carbonate. Write a balanced net ionic equation for the reaction.
Products: PbCO3 and NH4NO3
NIE: Pb2+(aq) + CO32-(aq) --> PbCO3(s)
500
How many grams of the precipitate are formed when 20.0ml of 1.35M FeCl3 reacts with 35.0ml of 1.65M AgNO3 in this reaction? If you actually isolate 6.83g, what is the percent yield?
FeCl3(aq) + 3AgNO3(aq) --> 3AgCl(s) + Fe(NO3)3(aq)
(Limiting reagent: AgNO3)
8.28g AgCl formed
percent yield: 82.5%
500
A 360.0g piece of rebar (a steel rod used for reinforcing concrete) is dropped into 425 mL of water at 24.0 °C. The final temperature of the water was measured as 42.7 °C. Calculate the initial temperature of the piece of rebar.
Specific heat of rebar is 0.449 J/g oC,
water: 4.184J/g oC
248oC
500
Methane, CH4, is being considered for use as an alternative automotive fuel to replace gasoline. One gallon of gasoline could be replaced by 655g of CH4. What is the volume of this much methane at 25°C and 745 torr?
(R = 0.08206 (L*atm)/(mole*K))
1020 L