Overview
This lecture demonstrates proper techniques for measuring specific volumes of deionized (DI) water using various types of laboratory glassware for your first general chemistry experiment.
Measuring with Non-Analytical Glassware
- Use a 150 mL beaker to measure out a specified volume (e.g., 20 mL) of DI water.
- "Tare" (zero) the balance with the empty glassware before adding water by pressing the tare button.
- Add water to the required mark, then weigh the glassware plus water to determine the water's mass.
- Subtract the tared (zeroed) value to isolate the mass of only the water.
Measuring with Analytical Glassware
- Analytical glassware includes burets and volumetric pipettes for more accurate measurements.
- Do not place burets directly on balances; instead, dispense liquid into a tared beaker.
- Fill the buret to the zero mark at the top using a funnel; values increase going down.
- Place a tared beaker under the buret and dispense the required volume (e.g., 10 mL).
- Weigh the beaker with dispensed water to determine the mass.
Using Glassware for Volume Measurement
- For 50 mL of DI water, use Erlenmeyer flask, beaker, and graduated cylinder.
- For 10 mL of DI water, use buret and volumetric pipette.
- Read graduation marks correctly; orientation and zero points differ between glassware types.
Key Terms & Definitions
- Taring — Setting a balance to zero with a specific container on it, so only added contents are weighed.
- Analytical Glassware — Precision instruments like burets and pipettes used for accurate liquid measurement.
- Graduation Mark — Lines on glassware indicating volume levels.
- Deionized (DI) Water — Water purified to remove ions, used in laboratory experiments.
Action Items / Next Steps
- Replicate the measurement procedures with all assigned glassware.
- Perform any required calculations based on your measured values.
- Ask your TA if you have questions during the experiment.