Osmosis and Percentage Change Concepts

This video tutorial explains how to investigate the effect of osmosis on plant tissue, specifically using potatoes. It covers the setup of the experiment, including preparing potato cylinders and immersing them in different solutions. The video also details how to measure changes in mass and length, calculate percentage changes, and interpret the results by plotting graphs. The tutorial emphasizes the importance of understanding osmosis as a diffusion process and provides sample calculations to aid learning.

What is osmosis?

• The movement of water from a concentrated solution to a dilute solution through a permeable membrane.

• The movement of solutes from a concentrated solution to a dilute solution through a partially permeable membrane.

• The movement of water from a dilute solution to a concentrated solution through a partially permeable membrane.

• The movement of solutes from a dilute solution to a concentrated solution through a permeable membrane.

What is the effect of placing a plant cell in distilled water?

• The cell dissolves.

• The cell remains unchanged.

• The cell shrinks as water moves out.

• The cell expands as water moves in.

What is the first step in preparing the potato for the osmosis experiment?

• Boiling the potato.

• Peeling the potato.

• Freezing the potato.

• Cutting the potato into cubes.

Why is it important to use distilled water in the osmosis experiment?

• Because it is more readily available.

• Because it contains no dissolved substances that could affect osmosis.

• Because it has a higher temperature than tap water.

• Because it is cheaper than tap water.

What is the purpose of rolling the potato cylinders on paper towels after the experiment?

• To dry them completely.

• To remove surface moisture without forcing water out of the cells.

• To weigh them accurately.

• To make them easier to handle.

How do you calculate the percentage change in mass?

• Change in value divided by the original value multiplied by 100.

• Original value divided by the change in value multiplied by 100.

• Original value multiplied by the change in value divided by 100.

• Change in value multiplied by the original value divided by 100.

If a potato cylinder's mass increases from 1.56 grams to 1.81 grams, what is the percentage increase?

• 20.00%

• 16.03%

• 25.64%

• 10.00%

What happens to a potato cylinder in a concentrated sugar solution?

• It dissolves completely.

• It remains the same as no osmosis occurs.

• It loses mass as water moves out by osmosis.

• It gains mass as water moves in by osmosis.

Where does the line cross the x-axis on the graph of percentage change against sugar concentration?

• Where the concentration outside the cell is lower than inside.

• Where no osmosis occurs.

• Where the concentration outside the cell is higher than inside.

• Where the concentration outside the cell is the same as inside.

What is the significance of the point where the graph line crosses the x-axis?

• It represents the initial mass of the potato.

• It indicates the maximum osmosis rate.

• It marks the point of maximum mass gain.

• It shows the concentration where no net osmosis occurs.