Question

part a which of the following statements about water is not correct? it is responsible for much of the mass of the human body. it is composed of polar molecules. it has a relatively low heat capacity. it contains hydrogen bonds. it can dissolve many substances.

Explanation:

1. Analyze "It is responsible for much of the mass of the human body": The human body is about 60 - 70% water, so this is correct.
2. Analyze "It is composed of polar molecules": Water ($H_2O$) has a bent molecular geometry and a dipole moment due to the electronegativity difference between O and H, so it is polar. This is correct.
3. Analyze "It has a relatively low heat capacity": Water has a high specific heat capacity (4.18 J/g°C), meaning it can absorb a lot of heat with a small temperature change. So this statement is incorrect.
4. Analyze "It contains hydrogen bonds": Water molecules form hydrogen bonds between the hydrogen of one molecule and the oxygen of another. This is correct.
5. Analyze "It can dissolve many substances": Water is a polar solvent and can dissolve polar and ionic substances (like salts, sugars), so it can dissolve many substances. This is correct.

Answer:

It is composed of polar molecules. (Wait, no, let's re - evaluate. The question is which statement about water is not correct. Let's analyze each option:

• "It is responsible for much of the mass of the human body": Correct, the human body is mostly water.
• "It is composed of polar molecules": Water molecules are polar (due to the difference in electronegativity between O and H, leading to a bent shape and a dipole moment), so this is correct.
• "It has a relatively low heat capacity": Incorrect. Water has a high heat capacity (specific heat capacity of water is about 4.18 J/g°C, which is relatively high). This is the incorrect statement.
• "It contains hydrogen bonds": Correct, water molecules form hydrogen bonds with each other.
• "It can dissolve many substances": Correct, water is a universal solvent and can dissolve many ionic and polar substances.

So the answer is the option "It has a relatively low heat capacity".