Concentrated and dilute solutions
Same acid, different amounts
1. Concentrated and dilute solutions: from zero
2. Same formula, two labels
In Chapter 1, two iron equations use the same acid, H2SO4. One arrow says (dil), the other says (conc.).
Pick the right answer
Predict: what is the difference between dilute and concentrated sulphuric acid?
- A. They are two different compounds.
- B. Same acid; the concentrated one has much more acid in each volume.
- C. The dilute one has fewer H atoms in its formula.
Explanation
Dilute and concentrated sulphuric acid are the same compound, H2SO4; the concentrated one has much more acid in each volume. Diluting adds water and does not change the formula.
3. Concentrated solution
A solution has a dissolved substance, the solute, spread through a solvent such as water.
Concentrated solution
A solution with a large amount of solute in a given volume.
4. Dilute solution: add water
Dilute solution
A solution with a small amount of solute in a given volume.
Keep the same solute. Add water to raise the volume. Watch the particles spread out.
Volume of solution 100 mL
Solute particles in each 100 mL 8
5. Which is more concentrated?
Pick the right answer
Beaker A: 5 g of sugar in 50 mL of solution. Beaker B: 10 g of sugar in 500 mL. Which is more concentrated?
- A. A
- B. B, because it holds more sugar
- C. They are equally concentrated
Explanation
Beaker A is more concentrated: it has 5 50 = 0.1 g of sugar in each mL, while B has 10 500 = 0.02 g in each mL. Concentration compares the solute in each volume, not the total amount.
Fill in the blanks
Adding water to a solution makes it more _____.
Explanation
Same solute, more volume: a more dilute solution.
True or false?
Dilute sulphuric acid and concentrated sulphuric acid are different compounds.
Explanation
The statement is false: both are the same compound, H2SO4. What differs is the amount of acid in each volume.
6. Summary
- Concentrated: a large amount of solute in a given volume.
- Dilute: a small amount of solute in the same volume.
- Adding water dilutes a solution. The solute itself does not change.
Can you explain why 10 g of sugar can be dilute while 5 g is concentrated?
Reveal
Concentration compares the solute in each volume, not the total amount. 10 g of sugar in 500 mL is 10 500 = 0.02 g in each mL (dilute), while 5 g in 50 mL is 5 50 = 0.1 g in each mL (concentrated).