Question

question 9
1 pts
which of the following statements is not true?
○ water is essential for prokaryotic life.
○ water is essential for eukaryotic life.
○ water is polar.
○ water is the most abundant molecule in the earths atmosphere, making photosynthesis possible.
○ water stabilizes temperature.

question 10
1 pts
when an acid is added to water, the ph should ______.
○ cant tell without testing.
○ stay the same.
○ increase
○ decrease

Explanation:

Question 9

• Prokaryotic and eukaryotic cells both need water for life processes, so the first two statements are true.
• Water is a polar molecule due to its bent shape and electronegativity difference, so that statement is true.
• The most abundant molecule in Earth's atmosphere is nitrogen ($N_2$), not water. Water vapor is present but not the most abundant, and photosynthesis uses water from the environment (like soil for plants) not atmospheric water as the main source. So "Water is the most abundant molecule in the Earth's atmosphere, making photosynthesis possible" is false.
• Water has a high specific heat, so it stabilizes temperature, making that statement true.

• Acids increase the concentration of $H^+$ ions in water. pH is defined as $-\log_{10}[H^+]$. As $[H^+]$ increases, the pH value (which is a negative log of $H^+$ concentration) decreases. For example, pure water has a pH of 7 (neutral, $[H^+] = 10^{-7}$ M). Adding an acid like HCl increases $[H^+]$ (e.g., if $[H^+]$ becomes $10^{-3}$ M, pH becomes 3), so pH decreases.

Answer:

D. Water is the most abundant molecule in the Earth's atmosphere, making photosynthesis possible.

Question 10