Potassium fluoride has a solubility of 92 g of KF in 100 g of $\mathrm{H_2O}$ at 18 $\degree$C. Determine if adding 35 g of KF to 25 g of $\mathrm{H_2O}$ mixtures forms an unsaturated or saturated solution at 18 $\degree$C.

Draw structures of compounds that fit the following descriptions: (a) An $\alpha$, $\beta$-unsaturated ketone, C$_6$H$_8$O (b) An $\alpha$-diketone (c) An aromatic ketone, C$_9$H$_{10}$O
(d) A diene aldehyde, C$_7$H$_8$O

Potassium fluoride has a solubility of 92 g of KF in 100 g of $\mathrm{H_2O}$ at 18 $\degree$C. Determine if adding 42 g of KF to 50. g of $\mathrm{H_2O}$ mixtures forms an unsaturated or saturated solution at 18$\degree$C.

Winter wheat is planted in the early fall, grows over the winter when the weather is colder, and is harvested in the spring. As the temperature drops, the makeup of the plasma membrane of winter wheat changes. Unsaturated fatty acids replace saturated fatty acids in the phospholipids of the membrane. Why is this a suitable adaptation?

With the help of Figure 17.8, indicate whether the ring system in each of the following heterocyclic amines is (1) saturated (2) unsaturated or (3) fused. More than one choice may be correct for a given heterocyclic amine.

a. Pyrrole

b. Indole

c. Pyrimidine

d. Purine

Potassium nitrate has a solubility of 32 g of $\mathrm{KNO_3}$ in 100 g of $\mathrm{H_2O}$ at 20 $\degree$C. Determine if adding 19 g of $\mathrm{KNO_3}$ to 50. g of $\mathrm{H_2O}$ forms an unsaturated or saturated solution at 20 $\degree$C.

Lithium chloride has a solubility of 55 g of LiCl in 100 g of $\mathrm{H_2O}$ at 25 $\degree$C. Determine if adding 10 g of LiCl to 15 g of $\mathrm{H_2O}$ mixtures forms an unsaturated or saturated solution at 25 $\degree$C.

Potassium chloride has a solubility of 43 g of KCl in 100 g of H2O at 50 $\degree$ C. Determine if adding 15 g of KCl to 25 g of $\mathrm{H_2O}$ forms an unsaturated or saturated solution at 50 $\degree$ C.

With the help of Figure 17.8, indicate whether the ring system in each of the following heterocyclic amines is (1) saturated (2) unsaturated or (3) fused. More than one choice may be correct for a given heterocyclic amine.

a. Pyrrolidine

b. Imidazole

c. Pyridine

d. Quinoline

Choose the letter that best answers the question or completes the statement. Benzene is classified as an aromatic hydrocarbon because (A) it has a strong odor. (B) it contains only carbon and hydrogen. (C) it is a compound found in coal. (D) it has an unsaturated ring structure. (E) it has a saturated ring structure.

Cis versus trans. Why might most unsaturated fatty acids in phospholipids be in the cis rather than the trans conformation? D raw the structure of a 16-carbon fatty acid as Ca) saturated. (b) trans monounsaturated. and (c) cis monounsaturated.

Which of the following factors would tend to increase membrane fluidity?

1. A greater proportion of unsaturated phospholipids
2. A relatively high protein content in the membrane
3. A greater proportion of saturated phospholipids
4. A lower temperature

Which of the following processes are spontaneous, and which are nonspontaneous? (a) Freezing of water at $2^{\circ} \mathrm{C}$ (b) Corrosion of iron metal (c) Expansion of a gas to fill the available volume (d) Separation of an unsaturated aqueous solution of potassium chloride into solid $\mathrm{KCl}$ and liquid water

Label each of the following molecules as saturated or unsaturated.

(a) $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CHCH}_2$

(b) $\mathrm{C}_3 \mathrm{H}_6$

(c) CCC(C)C