Module 5 (Aqueous Chemistry)
Name all strong acids and bases
Acids: HI, HCl, HBr, HNO3, HClO3, HClO4, H2SO4
Bases:LiOH, NaOH, KOH, RbOH, CsOH, Sr(OH)2, Ba(OH)2
For the next reaction:
a) Determine oxidation numbers of each element
b) Write half reactions
c) Determine the oxidizing and reducing agents.
Zn + CuSO4 ---> ZnSO4 + Cu
a) Reactants: Zn=0, Cu=+2, S=+6, O=-2
Products: Zn=+2, S=+6, O=-2, Cu=0
b) Oxidation: Zn → Zn2++2e−
Reduction: Cu2++2e−→ Cu
c) Reducing agent: Zn
Oxidizing agent: Cu2+
Calculate the pressure (in atm) exerted by 1.82 moles of the gas in a steel vessel of volume 5.43 L at 69.5 °C
9.42 atm
A certain gas expands in volume from 2.0 L to 6.0 L at constant temperature. Calculate the work (in J) done by the gas if it expands:
a) against a vacuum
b) against a constant pressure of 1.2 atm
a) 0 J
b) -486 J
What is the enthalpy change when 25.0 g of ethanol burns completely (ΔHcomb = –1367 kJ/mol)?
-741.8 kJ
You mix a solution of silver nitrate (AgNO₃) with a solution of sodium chloride (NaCl).
1) What solid will form?
2) Write total ionic and net ionic.
3) Which are the spectator ions?
1) Silver chloride (AgCl)
2) Total: Ag (aq) + NO3 (aq) + Na (aq) + Cl (aq) ---> AgCl (s) + Na (aq) + NO3 (aq)
Net: Ag (aq) + Cl (aq) ---> AgCl (s)
3) Na & NO3 are the spectator ions
Assign oxidation numbers to all the elements in the following compounds and ion:
a) Li2O
b) HNO3
c) Cr2O72-
a) Li=+1, O=–2
b: H=+1, N=+5, O=-2
c: Cr=+6, O=-2
An inflated helium balloon with a volume of 0.55 L at sea level (1.0 atm) is allowed to rise to a height of 6.5 km, where the pressure is about 0.40 atm. Assuming that the temperature remains constant, what is the final volume of the balloon?
1.4 L
A lead (Pb) pellet having a mass of 26.47 g at 89.98°C was placed in a constant-pressure calorimeter of negligible heat capacity containing 100.0 mL of water. The water temperature rose from 25.50 °C to 23.17 °C. What is the specific heat of the lead pellet?
0.158 J/g°C
Find the enthalpy for the reaction:
Al(s)+Fe2O3(g)→Al2O3(g)+ Fe(l)
Fe(l) 12.40 kJ/mol
Al2O3(g) -1669.8 kJ/mol
Fe2O3(g) -822.2 kJ/mol
△Hrxn= ?
-822.2 kJ/mol
Predict what happens when a potassium phosphate solution (K3PO4) is mixed with a calcium nitrate [Ca(NO3)2] solution. Write a net ionic equation for the reaction.
3Ca2+(aq) + 2PO43−(aq) → Ca3(PO4)2(s)
For the next reaction:
A) Determine oxidation numbers of each element
B) Write half reactions
C) Determine the oxidizing and reducing agents.
Na + Cl2 --> NaCl
a) Reactants:Na=0, Cl2=0
Products: Na=+1, Cl=-1
b) Oxidation: 2Na → 2Na+ + 2e−
Reduction: Cl2 + 2e− → 2Cl−
c) Reducing agent:Na
Oxidizing agent: Cl2
A gas exerts a pressure of 55 atm at 27 °C. If the pressure is increased at 88 atm, what’s the final temperature?
480.24 K
A 45 g aluminum spoon (specific heat 0.88 J/g °C) at 24 °C is placed in 180 mL (180 g) of coffee at 85 °C unitl the temperature of the two become equal. What is the final temperature when the two become equal? Assume that coffee has the same specific heat as water.
81.95 C
Calculate ΔH°f (H2S)
H2S(s)+O2(g)→H2O(l)+SO2(g)
ΔH°f
H2O(l) -285.8 kJ/mol
SO2(g) -296.1 kJ/mol
ΔH°rxn. -1123.4 kJ/mol
541.5 kJ/mol
Calculate the molarity of a solution prepared by dissolving 5.85 grams of sodium chloride (NaCl) in enough water to make 250 milliliters of solution.
0.4 M NaCl
Suppose you have 30 ml of hydrochloric acid. You add 52 ml of a 1.10 M solution of sodium hydroxide to neutralize the hydrochloric acid. What is the molarity of the hydrochloric acid solution?
1.9 M HCl
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?
9.5 L
A 466 g sample of water is heated from 8.50 °C to 74.60 °C. Calculate the amount of heat absorbed (in kilojoules) by the water.
129 kJ
Using Hess's Law, find the enthalpy of the following reaction:
4C (s) + 2H2 (g) → 2C2H2 (g)
C(s)+ O2(g)→CO2(g) −393.5 kJ/mol
H2(g)+1/2O2(g)→ H2O(l) −285.8 kJ/mol
2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(l) -2598.8 kJ/mol
453.2 kJ/mol
Lead(II) nitrate is used in the manufacture of matches and special explosives. If a 721 mL of a 0.112 M lead(II) nitrate solution is mixed with 529 mL of a 0.33 M potassium iodide solution, how many grams of precipitate can be produced?
37.8 g PbI2
Suppose it takes 75 ml of a 3.7 M solution of potassium hydroxide to neutralize 90 ml of a solution of perchloric acid. What is the concentration of the perchloric acid solution?
3.1 M HClO4
0.34 mol of N2 and 0.12 mol H2 are in the same container at a preasure of 2.34 atm. Find the partial pressure of N2.
1.73 atm
A quantity of 1.435 g of naphthalene (C10H8), a pungent-smelling substance used in moth repellents, was burned in a constant-volume bomb calorimeter. Consequently, the temperature of the water rose from 20.28 °C to 25.95 °C. If the heat capacity of the bomb plus water was 10.17 kJ/ °C, calculate the heat of combustion of naphthalene on a molar basis; that is, find the molar heat of combustion.
-5.151 x 103 kJ/mol
Using Hess's Law, find the enthalpyof the following reaction:
C2H4(g) + H2(g) → C2H6(g)
C2H2(g)+H2(g)→ C2H4(g) −175.7 kJ/mol
C2H2(g)+2H2(g)→ C2H6(g) −312.0 kJ/mol
-136.3 kJ/mol