TASK SHEET 2: Properties of Liquids (Module 1B)
Analyze the following statements carefully. Tell whether the concept of the statement is a FACT or BLUFF.
1. If the IMFA of a liquid is strong, then there is a lesser force needed to break through the surface, and the greater the surface tension is.
2. A decrease in temperature decreases surface tension.
3. A liquid, with low IMFA, has lower viscosity.
4. An increase in temperature decreases viscosity.
5. The higher the IMFA, the lower is the vapor pressure.
6. An increase in temperature increases vapor pressure.
7. The higher the IMFA, the greater is the surface tension between molecules.
8. If a liquid has strong IMFA, evaporation is high, vapor pressure is low, and boiling point is high.
9. Substances with strong IMFA have high heat of vaporization because higher energy is needed to convert them into gaseous state.
10. The temperature increases at boiling point.
11. Substances that evaporate readily have strong IMFA.
12. Water is more viscous than oil.
13. Nonpolar molecules have higher melting and boiling points than polar molecules of similar molecular mass.
14. Surface tension is the result of the intermolecular force of attraction between liquid and solid materials.
15. If substance A has a stronger IMFA than substance B, then substance A has a higher vapor pressure than substance B.
16. A liquid boils when its vapor pressure is less than the pressure acting on the surface of a liquid.
17. If molecule X has a stronger IMFA than molecule Y, then molecule Y has a lower boiling point than molecule X.
18. When adhesive forces are greater than the cohesive forces within a liquid in a narrow tube, the surface liquid will curve downward.
19. If substance Q has polar molecules with complex structures, then it is highly viscous.
20. In a state of liquid-gas equilibrium, the rate of condensation is equal to the rate of sublimation.
21. In a laboratory test, it is concluded that substance M is harder to vaporize than substance N. Therefore, we can conclude that substance M has a stronger IMFA than substance N.
22. Surface tension is temperature dependent; it decreases as temperature increases.
23. If the external pressure rises, the boiling point of a liquid increases.
24. Glycerol (with 3 hydrogen bonds) is more viscous than water.
25. After some experiments, it is found out that molecule V has a lower boiling point than molecule W. Therefore, we can conclude that one mole of W requires more heat energy to vaporize.
26. Substance A evaporates the fastest compared to substance E and I. Then, we can conclude that it has the strongest IMFA.
27. Substance X, Y and Z has the following boiling points respectively: -186°C, -164°C and -42.1°C. It can be deduced that substance X has the strongest IMFA.
28. Substance I, L and Y has the following vapor pressures at 50°C respectively: 0.08 atm, 0.12 atm and 0.30 atm. It can be predicted that substance Y has the highest boiling point.
29. Water is the only natural substance that is found in all three phases.
30. Water is an odorless, colorless, tasteless liquid.
31. Water freezes at 212°F.
32. Water is known as the universal solvent because it can dissolve all chemical substances.
33. Water is the only substance that contracts when freezes.
34. At 1 atm, its melting point is 32°F and boiling point is 212°F.
35. Large amount of heat is needed to vaporize a given amount of water.