What volume of 0.12 M HBr can be prepared from 11 mL of 0.45 M HBr?

1. The stock volume and concentration are given along with the diluted concentration, so V2 is the unknown. 2. Rearrange the dilution equation to V2 = C1V1 / C2. 3. Convert the stock volume: 11 mL = 0.011 L. 4. Substituting gives V2 = 0.45 M x 0.011 L / 0.12 M. 5. The numerator is 0.00495 mol and dividing by 0.12 M gives 0.041 L, which is 41 mL. 6. The diluted concentration is a bit more than one fourth of the stock, so the volume should be a bit under four times 11 mL. 7. The value 0.0029 L comes from multiplying by 0.12 M rather than dividing by it. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.3 Molarity_