Gases
In a steel vessel of 20 L capacity we introduce a gas that, at a temperature of 18 oC exerts a pressure of 1.3 atm. What pressure would you exert at 60C?
P2 = 1,5 atm
Carbonate Calcium
CaCO3
KMnO4 + K2SO3 + HCl ⇌ MnO2 + K2SO4 + KCl + H2O
2KMnO4 + 3K2SO3 + 2HCl = 2MnO2 + 3K2SO4 + 2KCl + H2O
Calculate the H 0 of the reaction: C (s) + CO2 (g) 2 CO (g) Knowing that: CO (g) + 1/2 O2 CO2 H 0 = -283.0 kJ C (s) + O2 (g) CO2 H 0 = -393.5 kJ
∆H 0 = +172.5 kJ
What is the pH of a 0.0235 M HCl?
1.629
We have a sample of a gas that when at a temperature of 200C a pressure of 2.8 atm is exerted on it, the volume is 15.9 L. What volume will it occupy if, at the same temperature, the pressure drops to 1 atm?
V2 = 44,5 L
AlF3
Aluminum fluoride
K2Cr2O7 + HI + H2SO4 ⇌ K2SO4 + Cr2(SO4)3 + I2 + H2O
K2Cr2O7 + 6HI + 4H2SO4 = K2SO4 + Cr2(SO4)3 + 3I2 + 7H2O
Write the formation reaction of SH2 (g) and calculate its standard enthalpy of formation from the following data: ΔHf 0 SO2 (g): -296.4 kJ / mol ΔHf 0 H2O (liq): -285.9 kJ / mol SH2 ( g) + 3/2 O2 (g) → SO2 (g) + H2O (liq) ΔH 0 = -561.8 kJ / mol
Result: ΔHf 0 SH2 (g): -20.5 kJ / mol
What is the pOH of a 0.0235 M HCl?
12.371
A 750 mL hot air balloon is inflated with helium at 8 ° C and at a pressure of 380 atmospheres. What is the new volume of the balloon in the atmosphere at a pressure of 0.20 atm and a temperature of - 45 ° C?
1160 L
Cromic lithium
Li2CrO4
K2Cr2O7 + HCl ⇌ KCl + CrCl3 + Cl2 + H2O
K2Cr2O7 + 14HCl = 2KCl + 2CrCl3 + 3Cl2 + 7H2O
The standard enthalpy of formation of carbon dioxide (g) is -393.5 kJ / mol, that of liquid water -285.8 kJ / mol and that of methane (g) -748.0 kJ / mol. Calculate the standard enthalpy variation of the combustion reaction of methane gas.
ΔH 0 = -217.1kJ / mol
What is the pH of a 6.50 x 10-3 M KOH?
11.813
The tires of a car should be at 20 oC at a pressure of 1.8 atm. With the movement, they heat up to 50 oC, passing their volume from 50 to 50.5 liters. What will be the tire pressure after the ride?
P2 =1,96atm
Cobaltic Nitrate
Co(NO3)3
P + HNO3 + H2O ⇌ H3PO4 + NO
3P + 5HNO3 + 2H2O = 3H3PO4 + 5NO
Toluene (C7H8) is a very important liquid hydrocarbon in the organic industry, being used as a solvent, and also in the manufacture of dyes, dyes, medicines and explosives such as TNT. If a gram of toluene (C7H8) is burned, 42.5 kilojoules are released. a) What will be the value of your enthalpy of combustion? b) Calculate the standard enthalpy of formation of toluene, using Hess's law.
ΔHf 0 = +10.2 kJ / mol
What is the pH of a 6.2 x 10-5 M NaOH?
9.79
A hot air balloon has a volume of 500 m3 at normal atmospheric pressure and an air temperature of 40C. When it is rising, the pressure is 0.8 atm and with the gas burner we increase the temperature to 70C. What will be the new volume?
V2 =684,9m3
K2Cr2O7
Dicromato de potasio
H2S + NaMnO4 + HBr ⇌ S + NaBr + MnBr3 + H2O
2H2S + NaMnO4 + 4HBr = 2S + NaBr + MnBr3 + 4H2O
Calculate the variation of Gibbs free energy and equilibrium temperature, assumed constant H and S, for the oxidation of SO2 to SO3: SO2 + ½ O2 SO3. Data: Hf 0 SO3 (g) = -395.7 kJ / mol S 0 SO3 (g) = 255.9 J / mol K Hf 0 SO2 (g) = -296.4 kJ / mol S 0 SO2 (g) = 248.3 J / mol KS 0 O2 (g) = 204.8 J / mol K
H = -99.3 kJ / mol S = -94.8 J / mol K Teq = 1047 K
Calculate the molarity of a 250 ml solution in which 30 grams of sodium chloride (NaCl) is dissolved. Data: atomic weights Na = 23, Cl = 35.45.
2.04 M