If 250 mL of a 1:800 (v/v) solution are diluted to 1000 mL, what will be the ratio strength (v/v)?

Sure, let's break it down:

1. First, understand the initial solution: A 1:800 (v/v) solution means there is 1 volume part of the solute for every 800 volume parts of the solution. In this case, you have 250 mL of this solution.

2. Calculate the volume of the solute in the initial solution: Since the ratio is 1:800, in 250 mL of solution, the volume of the solute would be 250 mL / 800 = 0.3125 mL.

3. Dilute the solution to 1000 mL: Now, you're taking that 0.3125 mL of solute and diluting it with more solvent until the total volume of the solution is 1000 mL.

4. Calculate the new ratio strength: The volume of the solute hasn't changed, it's still 0.3125 mL. But now it's in 1000 mL of solution. So the new ratio strength (v/v) is 0.3125 mL : 1000 mL.

5. Simplify the ratio: To simplify this, divide both sides by the volume of the solute (0.3125 mL). This gives you a ratio strength of 1:3200 (v/v).

So, if 250 mL of a 1:800 (v/v) solution are diluted to 1000 mL, the new ratio strength (v/v) will be 1:3200.