When determining which tool was most likely used in a procedure where approximately 300 mL of water was measured, we should consider the common uses and capacities of various laboratory tools designed for measuring liquid volumes.
1. Volumetric Flask:
- Volumetric flasks are designed for precise measurement and mixing of specific volumes of liquid, usually in fixed and specific capacities like 100 mL, 250 mL, 500 mL, etc. They are not typically used for volumes like 300 mL because they are more precise and usually come in these more standard volumes.
2. Graduated Cylinder:
- Graduated cylinders are versatile and used for measuring a wide range of volumes accurately, from a few milliliters up to several hundred milliliters. They could measure 300 mL efficiently, but they are more for precise measurements rather than just mixing.
3. Pipette:
- Pipettes are designed for very precise measurements of relatively small volumes of liquid, ranging from a few microliters to a few tens of milliliters. Because 300 mL is a relatively large volume, it is highly impractical to use a pipette for this measurement.
4. Beaker:
- Beakers are commonly used for holding, mixing, and roughly measuring larger volumes of liquids. They are typically used when precision is less critical compared to a volumetric flask or a graduated cylinder and thus are more suited to round figures like 300 mL.
Given that the lab report shows that approximately 300 mL of water was used, the most likely tool used in this procedure is a beaker.
Therefore, the answer is:
a beaker.
