Density Of Liquids

Density of Liquids
Problem – What is the density of tap water and how can property such as density be used to identify unknown substances?
Hypothesis – This experiment will prove the density of water is less dense then any unknown substance.
Materials: Chemical splash goggles Laboratory balance Laboratory apron Graduated cylinder, 10 - mL. 6 Plastic micropipettes Unknown liquid Tap water
Safety – apron, goggles, fire, dangerous vapors, poison, disposal, hygiene
Procedure
1. Put on your goggles and lab apron. Obtain six micropipettes and number them 1, 2,3,4,5, and 6. Make sure each micropipette is dry and clean. 2. Place micropipette #1 on the laboratory balance. Measure its mass to the nearest 0.01 g and record this value in Data Table 1. 3. Fill the micropipette with tap water as completely as possible. Place it on the balance and measure its mass to the nearest 0.01 g. record the mass in Data Table 1. 4. Completely transfer the water in the micropipette into a dry graduated cylinder. Measure and record the volume of the water to the nearest 0.1 mL. (Note: if the graduated cylinder is made of glass, your eye must be at the same level as the bottom of the meniscus to measure the volume accurately. See figure 2-1) 5. Using micropipettes #2 and #3, repeat steps 2-4 so that you have three sets of mass and volume data for water. 6. Obtain 50 mL of an unknown liquid from your teacher. Use micropipettes #4, #5, and #6 and the preceding procedure to measure the mass and volume of three samples of the unknown. Record your measurements in Data Table 2. CAUTION: the unknown solution may be flammable or toxic, or they may give off hazardous vapors. Avoid skin contact and inhaling their