Question

the u - shaped tube model shows the effects of osmosis over time.
u - shaped tube immediately after a different solution is added to each side
u - shaped tube after time has passed
decide whether each event happened on the left side or the right side of the u - shaped tube over time. complete the table.

	left side	right side
solvent concentration increased
solution volume increased

Explanation:

Step1: Analyze Solute Concentration

- Initially, the right side has more solute (orange dots) than the left. Over time, solvent moves to the right (osmosis, from low to high solute concentration). So the right side’s solute concentration **increases** (since solvent leaves left, but wait—no: wait, solute can’t move (assuming semipermeable membrane to solute). Wait, the left side has fewer solute particles initially. After time, solvent moves to the right (because right has higher solute concentration initially). So left side: solvent leaves, so solute concentration (solute/volume) increases? Wait no, wait the diagrams: first diagram (initial) left has 3 solute, right has many. Second diagram (after time) left has 3 (wait no, left in second diagram has 2? Wait no, initial left: 3 solute, right: many. After time: left level is lower (solvent left), right level higher (solvent entered). So left: volume decreases, solute amount same → solute concentration (solute/volume) increases? Wait no, initial left: let's count solute. First diagram left: 3 orange dots. Right: ~10. Second diagram left: 3? Wait no, left in second diagram: 2? Wait maybe I miscounted. Wait the key is osmosis: solvent moves from low solute concentration to high solute concentration. So initial right has higher solute concentration (more solute per volume). So solvent (water) moves from left (low solute) to right (high solute). So:

- **Solute concentration increased**: Left side: solvent leaves, so volume decreases, solute amount same → solute concentration (solute/volume) increases? Wait no, wait initial left: solute count (let's say) 3, volume V1. After time, volume V1’ < V1 (since solvent left). So 3/V1’ > 3/V1 → solute concentration increases on left? But the right side: solute count is same (solute can’t move), volume increases (solvent enters), so solute concentration (solute/volume) decreases? Wait this contradicts. Wait maybe I got the initial solute wrong. Wait first diagram: left has 3 solute, right has ~10. Second diagram: left has 3 (wait no, left in second diagram: 2? Wait no, the left in second diagram has 2? Wait maybe the left’s solute count decreased? No, solute can’t move. So maybe the initial left has lower solute, right higher. So solvent moves right. So left: volume decreases (solvent leaves), solute same → solute concentration increases. Right: volume increases (solvent enters), solute same → solute concentration decreases. Wait but the table is “solute concentration increased”—so which side? Wait maybe I made a mistake. Wait the problem says “solute concentration increased” over time. Let's re-express:

Initial state:

- Left: low solute concentration (less solute per mL)
- Right: high solute concentration (more solute per mL)

Osmosis: solvent (water) moves from left to right (down its concentration gradient, i.e., from high water concentration (low solute) to low water concentration (high solute)).

After time:

- Left: volume decreases (water left), solute amount same → solute concentration (solute/volume) increases.
- Right: volume increases (water entered), solute amount same → solute concentration (solute/volume) decreases.

Wait but that would mean “solute concentration increased” is left side. But the initial analysis was wrong. Wait maybe the solute particles: initial left has 3, right has 10. After time, left has 3 (solute can’t move), volume left is lower (so 3 / smaller volume → higher concentration). Right: 10 / larger volume → lower concentration. So “solute concentration increased” is left side? But the answer I wrote earlier was wrong. Wait this is confusing. Maybe the key is the diagrams: first diagram (initial) right has more solute, second diagram (after time) right has more solute (count) but volume increased. Wait maybe the problem’s “solute concentration” is about the number of solute particles per unit volume, but maybe the left’s solute count is same, volume decreases → concentration increases. Right’s solute count same, volume increases → concentration decreases. So “solute concentration increased” is left side. But my initial answer was wrong. Wait I need to correct.

Wait let's look at the two U-tubes:

First (initial):

- Left: liquid level ~5 units, solute ~3.
- Right: liquid level ~5 units, solute ~10.

Second (after time):

- Left: liquid level ~2 units, solute ~3 (same count? Wait no, left in second has 2? No, solute can’t move. So left solute count is same. So left: volume 2, solute 3 → concentration 3/2 = 1.5. Initial: 3/5 = 0.6. So increased.

Right: volume ~8 units, solute ~10 → concentration 10/8 = 1.25. Initial: 10/5 = 2. So decreased.

So “solute concentration increased” is left side. But the initial answer was wrong. Wait this is a mistake. So I need to correct.

But maybe the problem’s “solute concentration” is considered as the number of solute particles, but no, concentration is amount per volume.

Wait maybe the orange dots are solute, and the left initially has fewer, right more. So solvent moves right. So:

- **Solute concentration increased**: Left (volume decreases, solute same → concentration up).
- **Solvent concentration increased**: Solvent (water) concentration is water/volume. Left: volume decreases, water amount decreases? No, solvent is water. Wait solvent concentration: water/volume. Left: water (solvent) leaves, so volume decreases, water amount decreases → water concentration (solvent concentration) decreases? Wait no, solvent is the liquid (water), solute is the orange dots. So solvent concentration is (volume of solvent)/total volume? No, solvent concentration is (amount of solvent)/volume. So left: amount of solvent (water) decreases (since it moves to right), volume decreases. So (water amount)/volume: if water amount decreases by x, volume decreases by x (since it’s a U-tube, the volume lost from left is gained by right). So (W - x)/(V - x) vs W/V. Let's take numbers: W=5, V=5 (initial left: water volume 5, total volume 5). After time: water volume 5 - x, total volume 5 - x. So (5 - x)/(5 - x) = 1. Initial: 5/5 = 1. No, that’s not right. Wait maybe solvent concentration is (water)/(total volume), and solute concentration is (solute)/(total volume). So initial left: water 5, solute 3, total volume 5. So solvent concentration (water/volume) = 5/5 = 1. Solute concentration 3/5 = 0.6. After time: water 5 - x, solute 3, total volume 5 - x. So solvent concentration (5 - x)/(5 - x) = 1. Solute concentration 3/(5 - x) > 0.6. Right: initial water 5, solute 10, total volume 5. Solvent concentration 5/5 = 1. Solute concentration 10/5 = 2. After time: water 5 + x, solute 10, total volume 5 + x. Solvent concentration (5 + x)/(5 + x) = 1. Solute concentration 10/(5 + x) < 2. So solvent concentration (water/volume) is always 1? That can’t be. I think I’m overcomplicating. The key is:

- **Solute concentration increased**: Left (solvent leaves, volume decreases, solute same → concentration up).
- **Solvent concentration increased**: Wait, solvent is water. If solvent moves to right, left has less water (solvent), so solvent concentration (water/volume) decreases? No, maybe “solvent concentration” is (water)/(solute + water), but that’s not standard. Alternatively, solvent concentration is (amount of solvent)/volume. So left: amount of solvent decreases, volume decreases. So (W - x)/(V - x) vs W/V. Let’s take x=2: initial W=5, V=5. After: W=3, V=3. So 3/3=1, same as initial. If x=3: W=2, V=2. Still 1. So solvent concentration (water/volume) is always 1? That can’t be. So maybe the question means “solvent (water) concentration relative to solute”, i.e., water per solute. So left: initial water/solute = 5/3 ≈1.67. After: (5 - x)/3. If x=2, (3)/3=1 < 1.67 → solvent concentration (water per solute) decreased. Right: initial water/solute = 5/10 = 0.5. After: (5 + x)/10. If x=3, 8/10=0.8 > 0.5 → solvent concentration (water per solute) increased. Ah! That makes sense. So “solvent concentration increased” is right side, because water per solute (solvent concentration relative to solute) increased on right (more water per solute particle) and decreased on left (less water per solute particle).

- **Solution volume increased**: Right side (since solvent moved there, so volume increased).

So correcting:

- Solute concentration increased: Left (solute per volume increased, since volume decreased, solute same).
- Solvent concentration increased: Right (water per solute increased, since water increased, solute same).
- Solution volume increased: Right (solvent added, so volume increased).

But the initial answer was wrong. Let's redo the table with correct reasoning:

| Event | Left side | Right side |
|--|--|--|
| Solute concentration increased | $\boldsymbol{\checkmark}$ | |
| Solvent concentration increased | | $\boldsymbol{\checkmark}$ |
| Solution volume increased | | $\boldsymbol{\checkmark}$ |

This makes sense now. The key was realizing solute concentration is solute/volume (left volume decreases, solute same → concentration up), solvent concentration (water/solute) increases on right (water increases, solute same → water per solute up), and solution volume increases on right (solvent enters, so volume up).

Answer:

Event	Left side	Right side
Solvent concentration increased	$\boldsymbol{\checkmark}$
Solution volume increased		$\boldsymbol{\checkmark}$