How much does 1 liter (34 oz) of water weigh?
The correct answer and explanation is :
Weight of 1 Liter (34 oz) of Water
1 liter (L) of water weighs 1 kilogram (kg) or 1000 grams (g). In imperial units, this is approximately 2.2 pounds (lbs) or 35.2 ounces (oz).
Explanation
Water has a density of 1 gram per cubic centimeter (g/cm³) or 1 kilogram per liter (kg/L) at 4°C (39.2°F), which is its most dense state. This means that every milliliter (mL) of water weighs exactly 1 gram, and since 1 liter equals 1000 milliliters, it follows that 1 liter of water weighs 1000 grams (1 kg).
However, the weight of water can slightly change with temperature and impurities:
- Temperature Effect:
- As water heats up, it expands, decreasing its density slightly. For example, at 25°C (77°F), the density is 0.997 g/cm³, making 1 liter of water weigh around 997 grams instead of 1000 grams.
- At boiling point (100°C or 212°F), water’s density drops further, making it even lighter per liter.
- Impurities and Dissolved Substances:
- If minerals or salts dissolve in water (like seawater), the density increases, making 1 liter weigh more than 1 kg.
- For instance, seawater has an average density of 1.025 g/cm³, meaning 1 liter weighs 1025 grams (1.025 kg).
Conclusion
Under normal conditions (room temperature and pure water), 1 liter of water weighs 1 kilogram or 2.2 pounds. This fundamental property is crucial in science, engineering, and daily life.