Experimemt 8: Water And Properties

Question 1

• is one of the most abundant compound on Earth.
• It is essential in all living organisms and necessary to sustain life.
• Its chemical components that consist of 2 hydrogen atoms and an oxygen atom covalently bonded together.
• Its unique physical properties, it can exists in three state of matter

Answer 1

Water

Question 2

• It is known to be a universal solvent due to its high polarity characteristics as a molecule.
• It exhibits different physical properties like solubility which allows to dissolve ionic compound, other polar molecules but it will repel non-polar molecules, surface tension which make a strong electrostatic interactions with itself and enables to produce a “skin” on water, strong enough to hold very light objects.

Answer 2

Water

Question 3

Since ___ is highly polar, almost all substances are in contact are dissolve on it and these substances are contaminants and impurities. One of the form of impurities are the hardness in water and these are the amount of calcium and magnesium salts in water. Hardness in water can be temporary and permanent hardness. These water impurities can be removed by several process of purification like boiling, distillation, and different procedure of treatment of water.

Answer 3

Water

Question 4

• is a process by which undesiredchemical compounds, organic and inorganic materials, and biological contaminants are removed fromwater.
• One major purpose is to provide clean drinking water.
• also meets the needs of medical, pharmacological, chemical, and industrial applications for clean and potable water.
• reduces the concentration of contaminants and impurities

Answer 4

Purification of water

Question 5

= A compound containing water molecules:

Answer 5

Hydrate

Question 6

= a compound that does not contain water molecules.

Answer 6

Anhydrous compound

Question 7

= property of a crystal releases water when exposed to an atmosphere with low vapor pressure, it becomes anhydrous.

Answer 7

Efflorescence

Question 8

= property of a crystal that absorbs water from the atmosphere with high vapor pressure, it becomes hydrated.

Answer 8

Deliquescence

Question 9

– a reaction between two solutions forming a solid substance

Answer 9

Precipitate

Question 10

• a chemical process of decomposition involving the splitting of a bond and the addition of the hydrogen cation and thehydroxide anion of water

Answer 10

Hydrolysis

Question 11

• the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.
• The property of thesurfaceof a liquid that allows it to resist an external force, due to the cohesive nature of its molecules.
• The cohesive forces between molecules in a liquid are shared with all neighboring molecules.

Answer 11

Surface Tension

Question 12

• Small insects such as the water strider can walk on water because their weight is not enough to penetrate the surface.

Answer 12

Walking on water

Question 13

A carefully placed small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then the needle will quickly sink

Answer 13

Floating a needle:

Question 14

• Common tent materials are somewhat rainproof in that the surface tension of water will bridge the pores in the finely woven material. But if you touch the tent material with your finger, you break the surface tension and the rain will drip through.

Answer 14

Don’t touch the tent!:

Question 15

• Normal urine has a surface tension of about 66 dynes/centimeter but if bile is present (a test for jaundice), it drops to about 55. In the Hay test, powdered sulfur is sprinkled on the urine surface. It will float on normal urine, but will sink if the surface tension is lowered by the bile

Answer 15

Clinical test for jaundice:

Question 16

• Disinfectants are usually solutions of low surface tension. This allow them to spread out on the cell walls of bacteria and disrupt them.

Answer 16

Surface tension disinfectants:

Question 17

These help the cleaning of clothes by lowering the surface tension of the water so that it more readily soaks into pores and soiled areas

Answer 17

Soaps and detergents:

Question 18

These help the cleaning of clothes by lowering the surface tension of the water so that it more readily soaks into pores and soiled areas.

Answer 18

Soaps and detergents:

Question 19

The major reason for using hot water for washing is that its surface tension is lower and it is a better wetting agent. But if the detergent lowers the surface tension, the heating may be unneccessary.

Answer 19

Washing with cold water:

Question 20

The surface tension of water provides the necessary wall tension for the formation of bubbles with water. The tendency to minimize that wall tension pulls the bubbles into spherical shapes

Answer 20

Why bubbles are round:

Question 21

:Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer.

Answer 21

Surface Tension and Droplets

Question 22

• is the movement of a fluid from an area of higherconcentration to an area of lower concentration.
• the movement of particles down a concentration gradient.
• is a result of the kinetic properties of particles of matter.
• The particles will mix until they are evenly distributed.

Answer 22

Diffusion

Question 23

• is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air.
• is a measure of the amount of suspended sediment and visible particles in a sample of water

Answer 23

Turbidity

Question 24

• is used as coagulants or flocculants (forming large particles).
• Alum causes them to clump together so that they can settle out of the water or be easily trapped by a filter.

Answer 24

Alum solution

Question 25

is a process of purifying a substance; or a miscible liquid with different boiling temperature; or soluble mixture.

Answer 25

Distillation

Question 26

is due to the present of mineral salts of carbonate, bicarbonates, chlorides & sulfates of Ca 2+, Mg 2+, Fe +3

Answer 26

Hardness in water

Question 27

= due to the presence of bicarbonate , HCO 3 – 1 & carbonate, CO 3 – 2 of
Ca 2+, Mg 2+, Fe +3 like calcium carbonate, magnesium carbonate and ferric carbonate can be removed by boiling or distillation.

Answer 27

Temporary hardness

Question 28

= due to the presence of chlorides, Cl – 1 and sulfates, SO 4 – 2 of Ca 2+,
Mg 2+, Fe +3 and can be removed by cation and anion exchange.

Answer 28

Permanent hardness

Question 29

= treated water, absence of minerals and removal of permanent hardness

Answer 29

Soft water