I need to convert 40mg/mL to 5mg/mL with distilled water. How much distilled water would I use to do this?
You want 1/8 the concentration, so make the volume 8 times as big.
If you started with 10ml, add 70ml of water to end up with 80ml.
If you started with 10ml, add 70ml of water to end up with 80ml.