Group 5 2C-PH

26 Julao, Karen Grace P. Date Performed: February 29, 201627 Lansang, Kyle Dillan T. Date Submitted: March 14, 201628 Liao, Dixee Allison O.29 Liscano, Bea Patrice G.30 Malabanan, John Wilfred T.31 Mallari, Patricia Angelique

Experiment No. 3Specific Gravity of Liquids and Solids

Abstract

The specific gravities of the liquid and solid samples were determined in the experiment. The liquid sample was a 95% ethyl alcohol and its specific gravity was determined using three instruments, namely, Baumé hydrometer, Mohr-Westphal Balance and Leach Pycnometer. Water was used as the standard liquid on the Leach

pycnometer ; the mass of the empty pycnometer, pycnometer with water and pycnometer with the liquid sample were determined separately and from the data gathered the specific density was computed. The Baumé hydrometer and Mohr-Westphal Balance give an instant reading and there is no need for computation compared to the leach pycnometer. The results of the three different instruments were not the same with each other. These may have been due to human errors such as

inaccurate measurements of the liquid sample and accuracy of the instruments, or they could have been caused by external inevitable factors. The solid sample in the experiment was copper sulfate crystals and its relative density was determined using a pycnometer and 95% ethyl alcohol as a standard liquid. The weight of the empty pycnometer was determined. The copper sulfate crystals and 95% ethyl alcohol were added separately to the pycnometer, which

is then weighed, giving the weight of the copper sulfate crystals and 95% ethyl alcohol sample. The pycnometer was filled with a 95% ethyl alcohol in which the powder is completely insoluble.The weight of the displaced liquid can then be computed, and hence it is the relative density of the copper sulfate crystals.

The experiment’s objective was to determine the specific gravities of the liquid and solid samples. The liquid sample used was 95% ethyl alcohol and its specific gravity was determined using three instruments: Baumé hydrometer, Mohr-Westphal Balance and Leach Pycnometer. In determining the specific gravity of 95% ethyl alcohol, the Baumé hydrometer and Mohr-Westphal balance were used. Water was used as the standard liquid on the Leach pycnometer. The mass of the empty pycnometer, pycnometer with water and pycnometer with the liquid sample were determined separately and from the data gathered the specific density was computed. The results of the three different instruments were different with each other. These may have been due to human errors such as inaccurate measurements of the liquid sample and accuracy of the instruments, or they could have been caused by external inevitable factors. The solid sample in the experiment was copper sulfate crystals and its relative density was determined using a pycnometer and 95% ethyl alcohol as a standard liquid. The weight of the empty pycnometer was determined. The copper sulfate crystals and 95% ethyl alcohol were added separately to the pycnometer, which is then weighed, giving the weight of the copper sulfate crystals and 95% ethyl alcohol sample. The pycnometer was filled with a 95% ethyl alcohol in which the powder is completely insoluble. The weight of the displaced liquid can then be computed, and hence it is the relative density of the copper sulfate crystals.

Question and Answer

1) Differentiate specific gravity and density.

The difference between density and specific gravity is that one is a ratio of the other.Density is the measure of the amount of mass per volume. Density is expressed by the formulaρ = m/V where ρ is the density, m is the mass, and V is the volume Specific gravity is a measure of density relative to the density of a reference substance. Specific gravity is also called relative density and is expressed by the formula: Specific Gravitysubstance = ρsubstance/ρreference. The reference material could be anything, but the most common reference is pure water. One example is salt water aquarium enthusiasts measure the amount of salt in their water by specific gravity where their reference material is fresh water.

2) If 54.96 mL of oil weighs 52.78 g, what is its specific gravity?

Density = massvolume Specific gravity =

ρ sampleρwater

=52.78 g

54.96mL = 0.9603

1

= 0.9603 = 0.9603

3) A pycnometer weighs 50.00 g. When filled with water, it weighs 100.0 g. When filled with oil, it weighs 94.00 g. Determine the specific gravity of the oil.

Given: Mass of empty pycnometer = 50.00 g Mass of pycnometer + water = 100.00 g Mass of Pycnometer + oil = 94.00 gMass oil = masspycnometer + oil – massempty pycnometer

Mass oil = 94.00 g – 50.00 g Mass oil = 44.00 gMass water = masspycnometer + water – massempty pycnometer Mass water = 100.00 g – 50.00 g Mass water = 50.00 gSpecific gravity = mass oil mass water Specific gravity = 44.00 g

50.00 g Specific gravity= 0.880

Given: Mass of empty pycnometer = 50.00 g Mass of pycnometer + water = 100.00 g Mass of Pycnometer + oil = 94.00 g

Massoil = masspycnometer + oil – massempty pycnometer

= 94.00 g – 50.00 g = 44.00 gMasswater = mass pycnometer + water – mass empty pycnometer = 100.00 g – 50.00 g

= 50.00 g

Specific gravity = massof oilmass of water

Specific gravity = 44.00 g50.00g

Specific gravity= 0.8800

4) An insoluble powder weighs 12.00 g. A pycnometer, weighing 21.00 g when empty, weighs 121.00 g when filled with water. When the powder is introduced into the emptied pycnometer, and the pycnometer is filled with water, the three together weigh 130.00 g. What is the specific gravity of the powder?Given: Mass of insoluble powder = 12.00 g Mass of empty pycnometer = 21.00 g (A) Mass of pycnometer + water = 121.00 g (B) Mass of pycnometer + insoluble powder = 33.00 g (C) Mass of pycnometer + insoluble powder + water = 130.00 g (D)

Specific gravity =C−A

B+C−A−D

Specific gravity = 33.00−21.00

121.00+33.00−21.00−130.00

= 4.00