Question

water causes ionically-bonded atoms to
a bond more strongly.
b dissociate.
c bond covalently.
d decompose.

question 26
which of the following is characteristic of carbohydrates?
a they contain c, h, o, with twice as many hydrogen as oxygen atoms.
b they provide much of the energy that the cell requires.
c they include sugars and starches.
d all of the above.

Explanation:

First Question (Water and ionically - bonded atoms)

• Option A: Water is a polar molecule and disrupts ionic bonds, it does not make them stronger. So A is incorrect.
• Option B: Ionic compounds dissociate in water (e.g., NaCl dissociates into $Na^+$ and $Cl^-$ in water). So water causes ionically - bonded atoms to dissociate.
• Option C: Ionic bonds and covalent bonds are different types of bonds. Water does not convert ionic bonds to covalent bonds. So C is incorrect.
• Option D: Decomposition is a chemical reaction where a compound breaks down into simpler substances, which is not what happens to ionically - bonded atoms in water (they dissociate, not decompose). So D is incorrect.

• Option A: Carbohydrates have the general formula $C_n(H_2O)_m$, which means the ratio of hydrogen to oxygen is approximately 2:1 (twice as many hydrogen as oxygen atoms) and they contain C, H, O. This is a characteristic of carbohydrates.
• Option B: Carbohydrates (like glucose) are a major source of energy for cells. They are broken down in cellular respiration to provide energy. This is a characteristic of carbohydrates.
• Option C: Carbohydrates include monosaccharides (sugars), disaccharides (sugars), and polysaccharides (like starch). This is a characteristic of carbohydrates.
• Option D: Since A, B, and C are all correct characteristics of carbohydrates, the answer is D.

Answer:

B. dissociate.

Question 26 (Characteristics of carbohydrates)