Figure 3 is a set of instruments for carrying out measurement of various physical quant. Study the figure carefully and use it to answer the questions that follow. a) Identify the instruments labelled

here are the answers to question 3.

3. Figure 3 is a set of instrument for carrying out measurement of various physical quant. Study the figure carefully and use it to answer the questions that follow.

a) Identify the instruments labelled A, B, C, D, and E.

• A: Hydrometer
• B: Volumetric flask (specifically, a 250ml volumetric flask)
• C: Thermometer
• D: Dropper / Pasteur pipette
• E: (Not visible in the figure)

b) State one (1) use of each of the following instruments A, B, C, D and E.

• A: Used to measure the density or specific gravity of a liquid.
• B: Used to prepare solutions of a precise volume or concentration.
• C: Used to measure the temperature of a substance.
• D: Used to transfer small, unmeasured volumes of liquid drop by drop.
• E: (Not visible in the figure)

c) Describe how instrument D is used.
Instrument D (a dropper/pipette) is used by squeezing the rubber bulb (or top) to expel air, then placing the tip into the liquid and releasing the bulb to draw liquid into the tube. To dispense the liquid, the bulb is gently squeezed again to release drops or a small stream of the liquid.