A chemistry lab has 150 mL of a solution initially. If 45 mL is used in an experiment and then 20 mL more is added, how much solution is left?

Fri, 17 Apr 2026 08:40:38 +0000

**How Much Solution Remains in a Chemistry Lab? Understanding Use, Change, and Accuracy** Ever wondered how precise measurements affect real-world lab work? A common scenario involves starting with 150 mL of a chemical solution. In an experiment, 45 mL is carefully removed, and later, 20 mL is added back—raising the question: how much solution flows through the lab’s volume meter now? This simple math puzzle reflects growing interest in accurate lab tracking, especially among students, hobbyists, and professionals seeking clarity. With so many experimenting with chemistry at home and in labs across the US, getting the numbers right supports safety, resource management, and learning. The initial volume is 150 mL. When 45 mL is used, the remaining volume drops to 105 mL (150 – 45 = 105). Adding 20 mL restores part of that volume, resulting in 125 mL total (105 + 20 = 125). This straightforward shift in volume illustrates more than counting—it reveals how careful science management ensures precision. The final amount reflects both use and replenishment, avoiding errors that could compromise results or safety. Though it seems basic, correctly calculating lab volumes supports reliable outcomes across education and industry. The scenario also mirrors real usage patterns: experiments often consume and refill solutions to maintain workflow. Understanding these small but vital adjustments helps prevent waste, supports better planning, and builds confidence in lab practices. For those engaged in hands-on chemistry, whether in school or personal exploration, knowing how volumes change reinforces responsible habits.