Homework #13

20.

a. a tomato.

b. pure water.

c. milk of magnesia.

21. Because on the pH scale there is a ten increment difference, a solution at pH 4.0 is 100x more acidic than a solution at pH 2.0.

22.

Too low pH:

1) Fish egg development impaired, which harms the process of reproduction. 

2) Increased concentrations of metal ions in natural waters by leaching metal ions from surrounding soil.

High pH:

3.Scales on fish dissolve organic materials.

23. Polar molecules are molecules whose ends have opposite and asymmetrical charges. Polar molecules because “the opposites attract” cause the molecules to attract. Non-polar molecules have the same charge ends which make the ends repel one another.

24. Because water and ethanol are polar substances, you would choose the lamp oil to dissolve the nonpolar molecular substance.

25. Salt dissolves in water because it homogeneously mix throughout the solution. Salt cannot dissolve in cooking oil because it creates a suspension, and the salt particles cannot be fully mixed throughout.

26. This relationship between solvents that dissolve solutes with similar electrical charges is described as "like dissolves like."

27. Water would not be able to dissolve the grease on dishes because oil is composed of nonpolar molecules. The dishes to remove the grease would have to be washed with a solution composed of non-polar molecules.

33.

a. Nonpolar materials are likely to be found in these cleaners.

b. Using these cleaners would be more effective than washing with water because since water molecules are polar, they would not dissolve the grease off of the mechanics' hands. Instead, the water would sort of roll off of their hands without them being cleaned.

35. Fluorine has the highest electronegativity of any element, so it would make a negative end of the polar bond. Hydrogen has less negative charges than fluorine, so it would have a partial positive charge of the polar bond.