- The enthalpy change of solution formation for KBr in water is +19.8 kJ/mol. However, the solubility of KBr is very high in water. This is due to:
- dipole-dipole attractions.
- a higher entropy (disorder) in solution compared to the solid.
- an exothermic solvation process.
- solvent-solvent interactions.
- an endothermic solvation process.
- Which of the following is/are immiscible in water?
- CCl4(carbon tetrachloride)
- CH3OH (methanol)
- both a and c
- all three
- Which of the following solutes will produce the largest total molality of solute particles when dissolved in water?a) 2 moles of NaCl
- 1 mole of ethanol
- 1 mole of Mg(Cl)2
- 2 moles of methanol
- A 5.50 g sample of a compound is dissolved in 250 grams of benzene solvent. The freezing point of this solution is 1.02° C below that of pure benzene. What is the molar mass of this compound? (Kf for benzene = 5.12° C/molal)
- Calculate the molality of ethanol (CH3CH2OH) in a water solution which is prepared by mixing 39.5 grams of ethanol with 100.0 g of H2O at 20° C.
- 0.086 m
- 0.094 m
- 1.24 m
- 8.59 m
- A 20.0 gram sample of methanol (CH3OH) was dissolved in 30.0 grams of water. The mole fraction of methanol is:
- If the vapor pressure of water at 90° C is 0.692 atm, then what is the vapor pressure of a solution (in atm) made by dissoving 1.00 mole of urea in 1.00 kg of water?
- The colligative property of boiling point elevation is due to:a) osmosis of solute particles.
- lowered vapor pressure of solution relative to pure solvent.
- ion-dipole interactions.
- the chemical nature of the solute.
- none of these.
- The standard enthalpy of combustion of acetylene (C2H2) is -1410 kJ/mol. How many kJ of heat are liberated by the combustion of 13.0 g of acetylene?
- 13 kJ
- 705 kJ
- 18,326 kJ
- 1410 kJ
- 780 kJ
- The standard enthalpy of formation of CO (g) refers to the DH of which reaction below?
- 2 C (graphite) + O2(g) --> 2 CO(g)
- C (diamond) + 1/2 O(g) --> CO(g)
- C (graphite) + 1/2 O2(g) --> CO(g)
- C (graphite) + O2(g) --> CO(g)
- Identify the INCORRECT statement below:
- Energy is the capacity to do work or transfer heat.
- According to the First Law of Thermodynamics, the total amount of energy in the universe is constant.
- Endothermic processes require the absorption of energy to occur, corresponding to a positiveDH.
- The Gibbs free energy G of a system is increasing in any spontaneous process.
- A chemical reaction taking place in a calorimeter causes the temperature to rise 7.5° C. The addition of 50 kJ of energy to the same calorimeter by an electrical heater increases its temperature 2.5° C. What is DH of the chemical reaction?
- 16.7 kJ
- -16.7 kJ
- -150 kJ
- 150 kJ