Question

question 7
0.5 pts
sometimes when i have my morning coffee, which i drink black with no sugar, i notice a thin film floating on top of the coffee. since i have just read through the last background information, i now realize the nature of this substance and so i turn to my friend exclaiming, “look at this ______ in my coffee!”

hint: if a substance is floating on top of water, it must not like water...

• hydrophobic substance
• hydrophilic substance
• glucose
• miscibility

Explanation:

To solve this, we analyze the properties: A substance floating on water (coffee has water) doesn't "like" water. Hydrophobic substances repel water (don't mix, can float), hydrophilic attract water (dissolve/mix), glucose is hydrophilic (dissolves), and miscibility refers to mixing ability (not a substance type here). So the floating substance is hydrophobic.

Answer:

A. Hydrophobic substance