Water: Difference between revisions
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Water can be safely discarded into the environment | Water can be safely discarded into the environment | ||
==See Also== | ==See Also== | ||
==References== | ==References== | ||
<references/> | <references/> | ||
[[Category:Natural Materials]] | [[Category:Natural Materials]] |
Revision as of 03:26, 16 June 2019
Chemical formula | H2O |
---|---|
OTP appearance | clear liquid |
Index of refraction | 1.333 |
Molar Mass(g/mol) | 18 |
Enthalpy of Formation(kJ/mol) | −187.80 |
Density(g/cc) | 1 |
Melting Point(°C) | 0.1 |
Boiling Point(°C) | 100 |
Solubility in ethanol(g/L) | misc |
NFPA 704 |
Water, in the English language, is an inexact term. This article deals with the chemical compound H2O: pure water.
Uses
Primary
- Drinking water is essential to human life
- In chemistry, it is a common polar solvent
- Ice is a key thermal absorption material
Secondary
- Expansion on freezing is a key mechanic in early stone splitting
Natural occurrence
- Water occurs naturally
- as fresh water (ultimately derived from rain)
- Rain
- Springs
- Rivers
- Lakes
- and salt water from
- oceans
- seas
- salt lakes
- brine deposits
- as fresh water (ultimately derived from rain)
- Structural water occurs in many minerals
- Many plants contain an abundance of water
Hazards
- Drowning
- Overconsumption (>= 2L/hr for multiple hours when normally hydrated) can lead to hyponatremia
Production
Extraction
Synthesis
from hydrogen gas
- Burn hydrogen in air, directing the combustion products to a condenser
- 2 H2 + O2{H2O(v)combustion}→
- 2 H2 + O2
- Condense the water formed
As a side product
Many chemical reactions, particularly acid/base reactions (e.g. acetic acid and calcium hydroxide), produce water as a side product.
- 2 CHCOOH + Ca(OH)2 → Ca(CH3COO)2 + 2 H2O // acetic acid and calcium hydroxide produce calcium acetate and water
Testing
Quantitative tests
- Density 1.0
- Melting point 0.1°C
- Boiling point 100°C
- pH 7.0
Qualitative tests
- Visual: Clear, colorless
- Smell: None
- Taste: Characteristic
- Approximate Viscocity : Characteristic
Purification
Filtration
- Passing water through clean, fine sand will remove some microorganisms.
- Passing water through charcoal or activated charcoal will remove toxins such as cyanide.
Arranging a filter with layers of sand and charcoal is an effective way to produce relatively clean (unpotable) water. It should still be boiled before drinking.
Distillation
- Distilled water is water that has been condensed from a gas. In simple cases this will render it both completely free of contaminants and totlly sterile.
- distil water
- discard residue
- distillate is distilled water
- NB: Some contaminants form fixed gaseous mixtures with water. (e.g. ammonia, ethanol, sulfuric acid) These are not easily removed by simple distillation.
Other
- The mineral witherite is sometimes used for the removal of calcium and magnesium sulfates from water via precipitation
- 2 BaCO3(s) + CaSO4(aq) + MgSO4(aq) → CaCO3(s) + MgCO3(s) + BaSO4(s)
Storage
Store in watertight containers.
Disposal
Water can be safely discarded into the environment