Water Science Quiz
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Questions and Answers

What percentage of human blood is typically composed of water?

  • 70%
  • 100%
  • 50%
  • 90% (correct)

Which of the following is NOT a typical state of water found on Earth?

  • Gaseous
  • Solid
  • Liquid
  • Plasma (correct)

Besides its presence in human blood, what role does water play in living organisms?

  • Provides a medium for bodily reactions (correct)
  • Acts as a rigid structural component
  • Forms the pigment in the skin
  • Acts as a solid fuel source

Which of the following describes the location of water in its solid state?

<p>Polar ice caps and high mountains (B)</p> Signup and view all the answers

When water is present in the atmosphere, what form does it predominantly take?

<p>Water vapor (B)</p> Signup and view all the answers

Which method is NOT typically used in large-scale water purification for making it potable?

<p>Distillation (A)</p> Signup and view all the answers

In the electrolysis of water using Hoffman's voltameter, where is hydrogen collected?

<p>In test tube B, over the negative electrode (D)</p> Signup and view all the answers

What is the chemical formula for water?

<p>H2O (B)</p> Signup and view all the answers

Why is it necessary to add acid or salt to water for electrolysis?

<p>To make water a better conductor of electricity (D)</p> Signup and view all the answers

What happens to the boiling point of water when the pressure decreases?

<p>It decreases (B)</p> Signup and view all the answers

What is the melting point of pure ice?

<p>0°C (D)</p> Signup and view all the answers

Why is distilled water not recommended for drinking?

<p>Because it lacks necessary minerals and salts (D)</p> Signup and view all the answers

What is the ratio by volume of hydrogen to oxygen produced during the electrolysis of water?

<p>2:1 (A)</p> Signup and view all the answers

What effect does the presence of impurities have on the freezing point of water?

<p>It lowers the freezing point (B)</p> Signup and view all the answers

What property of water makes it suitable as a cooling agent in car engines?

<p>High specific heat (C)</p> Signup and view all the answers

Which of the following best describes why water is essential for plant life?

<p>It is crucial for the process of photosynthesis, as well as seed germination and growth. (A)</p> Signup and view all the answers

What function does sweating primarily play in the human body related to water?

<p>It regulates body temperature through evaporation. (A)</p> Signup and view all the answers

What is the main reason that ocean and sea water are not suitable for direct consumption?

<p>They have a very high concentration of dissolved substances, primarily salt. (A)</p> Signup and view all the answers

Which of the following is a characteristic of underground water from springs and wells?

<p>It has no suspended impurities or germs due to filtration through soil. (B)</p> Signup and view all the answers

What distinguishes rainwater from well water regarding dissolved impurities, according to the text?

<p>Rainwater has fewer dissolved impurities than well water. (D)</p> Signup and view all the answers

What chemical formula represents a molecule of water?

<p>H2O (D)</p> Signup and view all the answers

What is the relative molecular mass of water ($H_2O$)?

<p>18 amu (C)</p> Signup and view all the answers

Which of the following is NOT a process that adds water to the atmosphere?

<p>Photosynthesis in plants (C)</p> Signup and view all the answers

What term is given to the process of removing dissolved salts from sea or ocean water?

<p>Desalination (D)</p> Signup and view all the answers

When heating dry substances in a test tube, what is observed regarding water?

<p>Droplets of water are deposited on the upper part of the inner walls of the test tubes. (C)</p> Signup and view all the answers

What is the primary reason rainwater can carry impurities?

<p>It dissolves gases and collects dust particles in the air. (D)</p> Signup and view all the answers

What is the concept of 'water harvesting' in the context of this text?

<p>Techniques used to improve the availability of water resources (B)</p> Signup and view all the answers

Which of these is a source of surface water, according to the text?

<p>Rivers (C)</p> Signup and view all the answers

What is the name of the electricity produced by the flow of water from a dam?

<p>Hydroelectricity (A)</p> Signup and view all the answers

What is one way that water is transported throughout the body?

<p>Water transports products of digestion, gases and minerals within the body. (D)</p> Signup and view all the answers

Which of the following best describes the role of the water cycle?

<p>It regulates weather patterns and ensures water availability in various forms. (D)</p> Signup and view all the answers

Approximately what percentage of the Earth's total water is readily available for human consumption in rivers, lakes, and springs?

<p>1% (C)</p> Signup and view all the answers

Which of the following is NOT a typical type of impurity found in natural water?

<p>Synthetic chemicals (B)</p> Signup and view all the answers

What process is most effective for removing dissolved impurities from water?

<p>Distillation (B)</p> Signup and view all the answers

What is the primary characteristic of potable water?

<p>It must be free from harmful impurities and germs. (D)</p> Signup and view all the answers

Which of the following is NOT a desirable characteristic of potable water?

<p>It should have a slight odor. (A)</p> Signup and view all the answers

What classifies water as 'saline water'?

<p>It contains a high percentage of salt, making it unfit for drinking. (D)</p> Signup and view all the answers

What is the process of allowing suspended solids to settle at the bottom of a liquid, like in water purification?

<p>Sedimentation (A)</p> Signup and view all the answers

What substance might be added during sedimentation to help tiny particles settle faster?

<p>Potash alum (C)</p> Signup and view all the answers

What is the primary purpose of filtration in water treatment?

<p>To remove suspended particles. (A)</p> Signup and view all the answers

Which of these is NOT a method of water sterilization mentioned?

<p>Magnetic field treatment (C)</p> Signup and view all the answers

Which chemical is frequently used for sterilization in swimming pools?

<p>Chlorine (A)</p> Signup and view all the answers

What is the process called when air is blown into filtered water to kill micro-organisms?

<p>Aeration (B)</p> Signup and view all the answers

What is the term for water that is safe to drink?

<p>Potable water (D)</p> Signup and view all the answers

Which of the following is NOT a primary source of natural water as mentioned in the text?

<p>Oceans (B)</p> Signup and view all the answers

Which of these is the correct balanced chemical equation for the reaction of magnesium with water?

<p>Mg(s) + 2H2O(l) &gt; MgO(s) + 2H2(g) (D)</p> Signup and view all the answers

Which pair of liquids is considered immiscible?

<p>Water and oil (A)</p> Signup and view all the answers

What primarily causes temporary hardness in water?

<p>Bicarbonates of calcium and magnesium (C)</p> Signup and view all the answers

Which method effectively removes permanent hardness from water?

<p>Adding sodium carbonate (C)</p> Signup and view all the answers

Which of the following correctly describes the effect of sodium carbonate on hard water?

<p>It softens water by forming insoluble calcium and magnesium compounds. (A)</p> Signup and view all the answers

What observation would be expected when soap is added to hard water?

<p>The soap forms a white precipitate commonly called 'scum'. (A)</p> Signup and view all the answers

Which of the following is a major contributor to water pollution?

<p>Industrial and agricultural processes (C)</p> Signup and view all the answers

Why does the presence of salt in seawater affect its freezing point?

<p>Salt reduces the hydrogen bonding between water molecules, thus lowering the freezing point. (C)</p> Signup and view all the answers

What is the primary reason water is effective as a cooling agent in engines and factories?

<p>Water's high specific heat capacity allows it to absorb a large amount of heat with minimal temperature increase. (D)</p> Signup and view all the answers

Which of the following illness can be caused by water pollution?

<p>Typhoid (D)</p> Signup and view all the answers

What action would NOT help to prevent water pollution?

<p>Using non-biodegradable substances such as detergents (B)</p> Signup and view all the answers

How does the anomalous expansion of water benefit aquatic life in cold regions?

<p>It prevents the entire water body from freezing, because ice floats, creating an insulating layer on top of the liquid water. (A)</p> Signup and view all the answers

What is a crucial effect of water scarcity on plants?

<p>The earth will lose its green character (D)</p> Signup and view all the answers

What happens to the density of water when it cools from room temperature down to 4°C?

<p>The density increases gradually. (A)</p> Signup and view all the answers

Why do water pipes sometimes burst in colder parts of the world during winter?

<p>The ice that forms inside the pipes occupies more volume than the liquid water it was, increasing pressure that can break pipes. (C)</p> Signup and view all the answers

Which of these is an effective water management practice?

<p>Recycling water in industries (B)</p> Signup and view all the answers

At what temperature does water have its minimum volume and maximum density?

<p>4°C (C)</p> Signup and view all the answers

Why is water often referred to as the universal solvent?

<p>It has the ability to dissolve a large variety of solid, liquid, and gaseous substances. (B)</p> Signup and view all the answers

What is the difference between an unsaturated and a saturated solution?

<p>An unsaturated solution is a solution where more solute <em>CAN</em> be dissolved; saturated ones <em>CAN_NOT</em>. (B)</p> Signup and view all the answers

What is a characteristic of potable water?

<p>It should be free from suspended impurities and harmful germs. (C)</p> Signup and view all the answers

How does temperature generally affect the solubility of solid versus gaseous solutes?

<p>Solubility of solids increases with temperature while gases decreases with temperature. (D)</p> Signup and view all the answers

What is the effect of increased pressure on the solubility of gases in a liquid?

<p>It typically increases solubility. (B)</p> Signup and view all the answers

What is the significance of 0°C in relation to water?

<p>Water can exist in all three states of matter at this temperature (C)</p> Signup and view all the answers

What are the roles of dissolved gases in natural bodies of water?

<p>They are essential for the survival of marine life and for plant growth. (A)</p> Signup and view all the answers

What happens when water is heated to temperatures above 2000°C?

<p>It undergoes electrolysis, forming hydrogen and oxygen gas. (C)</p> Signup and view all the answers

What is produced when water reacts with active metals such as sodium or potassium?

<p>Metallic hydroxides and hydrogen gas (C)</p> Signup and view all the answers

What distinguishes the chemical behavior of water with metallic oxides versus non-metallic oxides?

<p>Water produces alkaline solutions with metallic oxides, and acidic solutions with non-metallic oxides. (C)</p> Signup and view all the answers

What happens to anhydrous copper sulfate when water is added to it?

<p>Its color changes from white to blue. (C)</p> Signup and view all the answers

What is a significant reason why distilled water is not considered ideal for drinking?

<p>It does not contain any minerals that are beneficial for human health. (C)</p> Signup and view all the answers

What is the primary reason for water's anomalous behavior?

<p>Water expands below 4°C. (A)</p> Signup and view all the answers

Which gases, when dissolved in water, are stated to have biological importance?

<p>Oxygen and carbon dioxide (B)</p> Signup and view all the answers

What is typically formed when hard water reacts with soap?

<p>Scum (D)</p> Signup and view all the answers

Which method can be used to remove temporary hardness from water?

<p>Boiling (D)</p> Signup and view all the answers

Where does the triple point of water occur?

<p>At 0.01 °C (D)</p> Signup and view all the answers

Which of the following is NOT a major cause of water pollution?

<p>Water evaporation (A)</p> Signup and view all the answers

What process is used in water softeners to remove permanent hardness?

<p>Ion exchange (A)</p> Signup and view all the answers

Which of these are considered waterborne diseases?

<p>Cholera, typhoid fever, giardiasis (A)</p> Signup and view all the answers

Which of the following is a method of water conservation?

<p>Drip irrigation (A)</p> Signup and view all the answers

Which substance is present when temporary hardness is being removed from water by boiling?

<p>Calcium Carbonate (D)</p> Signup and view all the answers

What is the cause of thermal water pollution?

<p>Increase or decrease in water temperature (A)</p> Signup and view all the answers

What is the process of treating and reusing water that has been contaminated called?

<p>Water recycling (A)</p> Signup and view all the answers

Which of these is a cause of permanent hardness in water?

<p>Dissolved sulfates and chlorides of calcium and magnesium (D)</p> Signup and view all the answers

Flashcards

Importance of Water for Life

Water is crucial to all life forms and makes up a significant portion of their body mass. It's like the 'lifeblood' of living organisms.

Water as a Medium for Reactions

Water plays a vital role in the chemical processes that occur within living organisms. It acts as a solvent and medium for reactions.

Water's Role as a Solvent

Water's ability to dissolve various substances makes it essential for transport and nutrient absorption in organisms. It's like a universal 'carrier' in the body.

Water's States of Matter

Water exists in all three states of matter - solid (ice), liquid (water), and gas (water vapor). It's like a shapeshifter in the natural world.

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Water Scarcity and Its Impact

Water scarcity, caused by factors like drought or overuse, can harm plant growth and negatively impact ecosystems.

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Desalination

The process of removing dissolved salts from sea or ocean water to make it drinkable.

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Natural Water

Water that is naturally found in rivers, lakes, oceans, and underground.

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Hard Water

Water that contains a high concentration of dissolved minerals, mainly calcium and magnesium.

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Soft Water

Water that contains low concentrations of dissolved minerals, especially calcium and magnesium.

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Water Cycle

The continuous movement of water on, above, and below the surface of the Earth. It involves evaporation, condensation, and precipitation.

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Evaporation

The process of water turning from liquid to vapor and rising into the atmosphere.

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Condensation

The process of water vapor in the atmosphere cooling down and turning back into liquid water, forming clouds.

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Precipitation

Any form of water falling from the atmosphere to the Earth, including rain, snow, sleet, and hail.

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Transpiration

The process of plants releasing water vapor into the atmosphere through their leaves.

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Water Scarcity

The state of having insufficient water supply to meet the needs of people, plants, and animals.

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Water Pollution

The contamination of water sources by harmful substances, such as chemicals, sewage, or industrial waste.

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Water Purification

The process of cleaning and treating contaminated water to make it safe for drinking and other uses.

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Water Harvesting

Techniques used to collect and store rainwater to increase water availability.

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Hydroelectricity

The process of generating electricity using the flow of water from dams or rivers.

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Percentage Proportion of Water

The amount of water present in a substance, expressed as a percentage.

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What is electrolysis?

A process that breaks down a compound into its constituent elements by passing an electric current through it.

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What is a cathode?

The negative electrode in an electrolytic cell.

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What is an anode?

The positive electrode in an electrolytic cell.

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What is distilled water?

Water that has been purified through a process called distillation, which removes all impurities, including minerals and salts.

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What is water's chemical formula?

A compound made up of two hydrogen atoms and one oxygen atom.

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What is evaporation?

The process of water changing from a liquid to a gas.

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What is condensation?

The process of water changing from a gas to a liquid.

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What is specific heat?

The amount of heat energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius.

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What happens to water when it freezes?

When water freezes into ice under pressure, it expands.

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What is the melting point?

The temperature at which a substance changes from a solid to a liquid.

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Sedimentation

A process where suspended impurities settle at the bottom of a liquid.

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Filtration

A process of separating solid particles from a liquid by passing through a filter.

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Sterilization

The process of removing germs from water.

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Potable Water

Water that is safe for drinking.

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Saline Water

Water containing a high amount of salt, making it unsuitable for drinking or irrigation.

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Aeration

Adding air to water, which can kill harmful microbes.

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Chlorination

Chemicals that kill bacteria and germs in water.

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Chemical Treatment

Chemicals like chlorine and ozone used to kill bacteria and germs.

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Exposure to Air and Sunlight

A method of killing bacteria by exposing water to sunlight and oxygen.

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Mineral-Rich Water

Water containing minerals like sodium, calcium, magnesium, iron, etc.

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Saline Water

Water containing a high level of dissolved minerals, often called 'table salt'.

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Groundwater

Water that is naturally filtered through layers of sand, gravel, and rock.

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Tap Water

Water that is safe to drink after undergoing purification processes.

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Balanced Chemical Equation

A chemical equation where the number of atoms of each element on the reactant side equals the number of atoms of that element on the product side, ensuring mass conservation.

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Miscible Liquids

Liquids that can dissolve in each other to form a homogeneous mixture, like water and alcohol.

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Immiscible Liquids

Liquids that do not dissolve in each other and form separate layers when mixed, like oil and water.

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Temporary Hardness

Hardness in water caused by dissolved bicarbonates of calcium and magnesium, which can be removed by boiling.

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Permanent Hardness

Hardness in water caused by dissolved chlorides and sulphates of calcium and magnesium, which cannot be removed by boiling.

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Removal of Hardness

A method to soften hard water by removing calcium and magnesium ions.

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Effect of Sodium Carbonate on Hard Water

A chemical reaction where sodium carbonate (washing soda) removes calcium and magnesium ions from hard water, leading to softer water.

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Observations on Soap and Hard Water

The formation of a white, insoluble precipitate (scum) when soap is added to hard water.

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Observations on Soap and Soft Water

The ability of soap to lather freely in soft water, without forming scum.

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Effects of Water Pollution

Water pollution can cause various illnesses, harm aquatic ecosystems, and make water undrinkable.

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Prevention of Water Pollution

Actions taken to prevent water pollution by managing waste, using eco-friendly products, and safeguarding water sources.

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Why does seawater freeze at a lower temperature than freshwater?

Seawater's freezing point is lower than freshwater's due to the presence of salt, which acts like an antifreeze.

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How does water work as a cooling agent?

Water absorbs heat effectively, preventing overheating in engines, machines, and factories.

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What causes land and sea breezes?

Water's ability to absorb and retain heat makes it a natural cooling agent, contributing to moderate climates in coastal areas.

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Why is water used in room coolers and hot water bags?

Water's high specific heat and anomalous expansion make it useful in room coolers and hot water bags.

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What is anomalous expansion of water?

Anomalous expansion refers to the unusual behavior of water, where its solid form (ice) is less dense than its liquid form.

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How does the density of water change when it cools?

When water cools, it contracts and becomes denser until 4°C. After that, it expands and becomes less dense, explaining why ice floats.

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What is the triple point of water?

The triple point of water is the specific temperature and pressure at which water can exist as a solid, liquid, and gas simultaneously.

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How does anomalous expansion benefit aquatic life in cold regions?

Anomalous expansion protects aquatic life in cold regions by preventing the entire body of water from freezing solid.

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What happens to water in lakes when the temperature drops?

As surface water cools and becomes denser, it sinks, maintaining a temperature of 4°C at deeper levels.

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Why do water pipes burst in winter?

When water freezes, it expands, leading to increased pressure in pipes. If the pressure is too high, the pipes can burst.

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Why is water called the universal solvent?

Water is known as the universal solvent because it can dissolve a wide range of substances.

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What is a solution?

A solution is a homogeneous mixture of a solute and a solvent, with water acting as the solvent.

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What is the difference between an unsaturated and a saturated solution?

An unsaturated solution can dissolve more solute, while a saturated solution cannot dissolve any more at a given temperature.

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What is a supersaturated solution?

A supersaturated solution contains more solute than a saturated solution and is achieved by heating the solution.

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How does temperature affect solubility?

The solubility of solid solutes generally increases with temperature, while the solubility of gases decreases with temperature.

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Anomalous Behavior of Water

The unusual property of water where it expands when it freezes, unlike most substances.

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Water as a Solvent

Water's ability to dissolve a wide variety of substances. It acts like a universal solvent.

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Change of States of Water

The process of water changing from one state (solid, liquid, or gas) to another.

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Dissolved Substances in Water

Harmful substances dissolved in water, such as heavy metals, pesticides, or industrial waste.

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Temporary Hardness of Water

The presence of dissolved bicarbonates of calcium and magnesium in water. It can be removed by boiling.

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Permanent Hardness of Water

The presence of dissolved sulfates and chlorides of calcium and magnesium in water. It can be removed through chemical treatment.

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Chemical Water Pollution

The contamination of water with chemicals or harmful substances.

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Thermal Water Pollution

The increase or decrease in water temperature, often caused by industrial processes.

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Drip Irrigation

A method of irrigation where water is supplied drop by drop to plants.

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Water Conservation

Using water efficiently and avoiding waste.

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Water Protection

Protecting water sources from pollution and preserving their quality.

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Recycling Polluted Water

Treating and reusing contaminated water instead of discharging it into the environment.

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Study Notes

Importance of Water

  • Water is vital for all life forms, comprising a significant portion of most living organisms.
  • It acts as a medium for reactions within living organisms.
  • Water dissolves various substances.
  • Water is used in everyday activities, from cleaning to agriculture.

Sources of Water

  • Water exists in liquid, solid (ice), and gaseous (vapor) forms.
  • Oceans, seas, rivers, lakes, and groundwater are major sources.
  • Glaciers and ice caps hold substantial freshwater reserves.
  • Precipitation, including rain and snow, replenishes water sources.
  • Atmosphere contains water vapor, forming clouds, fog, and mist.

Properties of Water

  • Water is essential for everyday needs: cleaning, drinking, agriculture, manufacturing, and energy generation.
  • Water regulates body temperature through sweating and evaporation.
  • Water facilitates biochemical reactions within organisms.
  • It's crucial for seed germination and plant growth, including photosynthesis.
  • Water dissolves minerals, gases, and digestive products, transporting them throughout the body.

Water Purification

  • Purification processes ensure safe drinking water.
  • Methods like distillation, filtration, and chemical treatments remove impurities and microbes.

Water Pollution and Control

  • Water pollution negatively impacts quality and suitability for use.
  • Pollution sources include industrial and agricultural runoff, sewage, and waste disposal.
  • Pollution prevention involves proper waste treatment, hygienic practices, and sustainable agricultural methods.

Water Scarcity Effects

  • Insufficient water negatively impacts plant growth.
  • Conservation and management strategies are crucial.

Water Cycle

  • Evaporation, condensation, and precipitation are part of the water cycle.
  • Water is a renewable resource cycling through various states.
  • The cycle regulates weather patterns and water availability.
  • Human activities can influence the water cycle and water quality.

Water Available for Human Consumption

  • A small percentage of Earth's water is readily available for human use (only 1%).
  • Careful and wise water use is essential to sustained access.

Impurities in Water

  • Natural water contains dissolved and suspended impurities, as well as microbes.
  • Impurities can be removed through different treatments like filtration, distillation, and disinfection.

Potable Water Characteristics

  • Potable water is safe to drink, and free of harmful contaminants.
  • It's characterized by being odorless, colorless, transparent and clear.
  • It should contain essential minerals and gases for health.
  • Absence of nitrates, heavy metals and other harmful compounds.

Saline Water

  • Some natural water sources (springs, wells) may have high salt content (over 2%), unfitting it for direct use.

Minerals in Water

  • Minerals like sodium, calcium, magnesium, and iron are part of some water sources.
  • Excessive levels of some minerals can be harmful.

Purification of Potable Water (Large Scale)

  • Water sources like rivers and lakes require extensive purification steps.

  • Sedimentation: Suspended particles settle out.

  • Filtration: Removes remaining suspended matter using sand, charcoal, and gravel beds.

  • Sterilization: Kills microbes using sunlight, chemicals (chlorine, ozone) or aeration, often a multi-step process.

Electrolysis of Water

  • Electrolysis separates water into hydrogen and oxygen gases.
  • Hoffman's voltameter demonstrates this process.

Physical Properties of Water

  • Water is a colorless, odorless liquid under normal conditions.
  • Taste is derived from dissolved substances.
  • Freezing point (0°C) and boiling point (100°C) are affected by pressure and impurities.
  • Water has a high specific heat capacity making it a good coolant.

Anomalous Expansion of Water

  • Water has a unique expansion characteristic on freezing where ice floats.
  • This property safeguards aquatic life in cold climates.

Water as a Solvent

  • Water is known as a universal solvent, dissolving many substances.
  • Solutions are mixtures of solute and solvent, with water commonly acting as the solvent.

Effect of Temperature & Pressure on Solubility

  • Solubilities of substances in water are influenced by temperature and pressure.
  • Solids tend to be more soluble in warm water, while gases become less soluble.

Dissolved Gases and Minerals

  • Dissolved gases and minerals in natural water are important for aquatic life and are part of overall water quality.

Tests for Water

  • Water's boiling and freezing points, and reaction with certain compounds, can indicate its purity.

Waterborne Diseases

  • Water contamination can lead to waterborne illnesses like cholera, typhoid, and giardiasis.

Water Conservation and Management

  • Wise use of water, water recycling and rainwater harvesting are key to responsible water management.
  • Proper treatment and handling of sewage, industrial waste and agricultural runoff are essential for water conservation.

Hard and Soft Water

  • Hard water contains high mineral content (calcium, magnesium).
  • Soft water has low mineral content.
  • Hardness can be reduced through processes like boiling, adding chemicals and ion exchange.

Water Pollution, Causes & Effects

  • Water pollution contamination from industrial waste, agriculture, sewage, and litter affects water quality for humans and ecosystems.
  • Water pollution can cause human illness and harm aquatic life due to pollution with dangerous chemicals.

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Description

Test your knowledge about the properties and roles of water in living organisms and the environment. This quiz covers topics such as the states of water, water purification methods, and the electrolysis of water. Perfect for students and enthusiasts of environmental science and biology.

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