What Is Water Our Lifeline Definition Properties Uses and Role in Life
There are certain components of earth that have their own specific role in this world. Most of these components are used by humans to keep themselves healthy and sane. For instance, we can take oxygen. Homo sapiens and other mammals cannot live without oxygen. Likewise, there is another substance, which is not only precious to everyone but also necessary for everyone. That component, as we read, is water.
Water is deemed as the most vital substance, which is required for all living forms. As water contains oxygen, it carries nutrients to cells of the body. Let us learn more about water in the article.
Water and its Structure
Water is a colourless, odourless substance, which is the main constituent of the earth’s hydrosphere. It has the ability to dissolve any substance and is a solvent. Although water is colourless, it appears to be blue because of the scattering of light. The main molecules of water are hydrogen and oxygen and its structure is H2O (2 hydrogen and 1 oxygen). Even though the structure is simple, its chemical and physical properties are complicated, and not easily understandable.
Water helps living organisms in both ways. One, as a living habitat for aquatic mammals and two, as hydrating plants and animals on the land. Water can also provide food and a home for marine animals, whereas, it can also provide water for living organisms on land, through rain, as water evaporates, travels through the atmosphere from the oceans, and pours as rain on the land. From this, we can understand how essential water is for our life.
Wastewater
Water that is used or contaminated by various substances is termed as waste water. By substances it means human waste, chemical compounds, scraps, garbage, oil, and other non-hygienic substances. It has been hazardous to the health of all living organisms, especially for the people who live near the gutter or contaminated areas. People with limited supply of fresh water suffer the most.
Usage of wastewater is deemed unhealthy as it contains chemical compounds like nitrogen and phosphorus. The wastewater is mostly generated from domestic places like homes and from industrial places like factories and construction sites. The waste sometimes is not cleaned thoroughly and is dumped in vast water bodies like rivers and lakes. This causes harm to the fish and also to the people who live beside these water bodies.
Due to the chemical compounds in wastewater, when mixed with oxygen, lead to the release of hazardous gases in the atmosphere. These phenomena cause various health problems and limit the usage of river and lake water.
Components of Wastewater
A component of wastewater includes the cleaning of sewage plants by several methods. These components associated with sewage treatment plants remove harmful and contaminated substances from the wastewater before releasing them. The major components include:
Grit chamber
Comminutors
Bar screens
Pre-aeration tank
Biological filters
Primary setting tank
Secondary settling tank
Aeration tank, etc.
Wastewater From Kitchen
The wastewater from kitchen is called Sullage. They are mostly liquid wastes from the basin of the kitchen, and from the bathrooms. Kitchen water is generated without human waste contamination, so it is known as sullage waste. This water consists mostly of the waste from food, the excess liquid that was used for cooking, wastes from washing used dishes, etc.
Kitchen water is different from normally occurring sewage water because kitchen water can be reused. They can be recycled and used to water plants as plants do not require clean water like us. They can also be used to dump water in toilets for flushing. There is a vast difference between sewage and sullage water and one needs to understand it better in order to keep our environment clean.
Difference Between Sewage and Sullage
Interesting Facts
Most freshwater is available as ice.
Some water may have come from comets.
Our body consists of 70% water.
Key Features
Water consists of two molecules hydrogen and oxygen.
Water carries nutrients to cells.
Water can dissolve more substances than any other liquid including sulphuric acid.
Wastewater treatment plants cost a ton. Hence why wastewater is not treated properly.
FAQs on Water Our Lifeline in Chemistry Structure Properties and Significance
1. What is water and what is its chemical formula?
Water is a chemical compound with the formula H2O, consisting of two hydrogen atoms covalently bonded to one oxygen atom.
- It is a polar molecule due to the difference in electronegativity between hydrogen and oxygen.
- The molecule has a bent (V-shaped) geometry with a bond angle of about 104.5°.
- Water exists naturally in three states: solid (ice), liquid (water), and gas (steam or water vapor).
2. Why is water called the universal solvent?
Water is called the universal solvent because it dissolves more substances than any other liquid due to its polarity and ability to form hydrogen bonds.
- Its partial positive (H) and partial negative (O) ends attract ions and polar molecules.
- It dissolves ionic compounds like NaCl by forming hydration shells around Na+ and Cl- ions.
- It also dissolves many polar covalent compounds such as sugar.
3. What are the physical properties of water?
The physical properties of water include high boiling point, high specific heat capacity, and high surface tension due to hydrogen bonding.
- Boiling point: 100°C (at 1 atm pressure).
- Freezing point: 0°C (at 1 atm pressure).
- Specific heat capacity: 4.18 J g-1 °C-1.
- Maximum density at 4°C (about 1 g cm-3).
4. What are the chemical properties of water?
The chemical properties of water include its ability to act as both an acid and a base and to participate in hydrolysis and redox reactions.
- Water is amphoteric, meaning it can donate or accept a proton.
- Self-ionization: 2H2O(l) ⇌ H3O+(aq) + OH-(aq).
- It reacts with active metals like sodium: 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g).
5. What is the pH of pure water and why?
The pH of pure water at 25°C is 7 because the concentrations of H3O+ and OH- ions are equal at 1.0 × 10-7 mol L-1.
- Water undergoes self-ionization: 2H2O(l) ⇌ H3O+(aq) + OH-(aq).
- The ionic product of water, Kw, at 25°C is 1.0 × 10-14.
- Since [H3O+] = [OH-], water is neutral.
6. What is hard water and how is it formed?
Hard water is water that contains dissolved calcium and magnesium salts, mainly Ca(HCO3)2 and MgSO4.
- It forms when water passes through limestone (CaCO3) or dolomite rocks.
- Temporary hardness is due to bicarbonates and can be removed by boiling.
- Permanent hardness is due to sulphates or chlorides and requires chemical treatment.
7. How can temporary and permanent hardness of water be removed?
Temporary hardness is removed by boiling, while permanent hardness is removed by chemical methods such as adding washing soda or using ion-exchange resins.
- Boiling decomposes bicarbonates: Ca(HCO3)2(aq) → CaCO3(s) + CO2(g) + H2O(l).
- Washing soda (Na2CO3) precipitates Ca2+ as CaCO3.
- Ion-exchange method replaces Ca2+ and Mg2+ with Na+ ions.
8. What is electrolysis of water?
Electrolysis of water is the decomposition of water into hydrogen and oxygen gases using electricity.
- Overall balanced reaction: 2H2O(l) → 2H2(g) + O2(g).
- Hydrogen is produced at the cathode and oxygen at the anode.
- An electrolyte such as dilute H2SO4 is added to increase conductivity.
9. Why does ice float on water?
Ice floats on water because it is less dense than liquid water due to its open hydrogen-bonded structure.
- In ice, water molecules form a rigid hexagonal lattice.
- This structure increases volume and decreases density.
- Liquid water has closer-packed molecules, making it denser than ice.
10. What is the role of water in chemical reactions?
Water acts as a solvent, reactant, and medium for many chemical reactions in laboratory and biological systems.
- It participates in hydrolysis reactions, such as ester hydrolysis.
- It acts as a solvent for acid–base reactions in aqueous solutions.
- It is involved in hydration reactions, for example: CaO(s) + H2O(l) → Ca(OH)2(aq).
