(Chemistry) Unit 4D Water Purification and Treatment Study Guide- Jaren Katz

What happens in Pre-Chlorination?

Pre-Chlorination is when chlorine, a powerful disinfecting agent, is added to kill disease-causing organisms.

What is chlorine gas?

(Cl₂) Chlorine Gas is bubbled into water. Chlorine Gas is not very soluble in water. It does react with water, however only to produce a water-soluble chlorine containing compound.

What are Trihalomethanes?

(THM's) Trihalomethanes are

What 3 processes does chlorination take place in the process of water treatment?

1) (Bubbles) Chlorine Gas 2) (NaOCl) Sodium Hypochlorite 3) Ca(OCl)₂ Calcium Hypochlorite

What are three optional and additional treatments used for drinking water treatments?

1) Aeration 2) pH 3) Fluordination

What three processes make up water's purification system?

1) Evaporation/Condensation, removes all dissolved substances. 2) Bacterial Action which converts dissolved organic contaminants into simple compounds. 3) Filtration through sand and gravel removes most of the suspended matter.

Explain what happens in The Hydrologic Cycle?

1) Evaporation: Thermal Energy from the sun causes water from the ocean to rise into the air and turn into water vapor. Then Water vapor droplets join together to make clouds. 2) Condensation: Then water vapor in the air cools down and turns back into liquid water. 3) Precipitation: This is when water (in the form of rain, snow, hail or sleet) falls from clouds in the sky. 4) Collection: This is when water that falls from the clouds as rain/snow is collected in the oceans, rivers, lakes, and streams. Most will soak into the ground and then will be collected as ground water.

What are 4 types of Home Water Treatments?

1) Filtration 2) Reverse Osmosis 3) Water Softening 4) Distillation

What are three techniques for purifying water?

1) Oil-Water separation 2) Sand Filtration 3) Charcoal Absorption

What is a filtrate?

A filtrate is the liquid collected after filtration has occurred.

What are adhesive forces?

Adhesive forces attract molecules of different substances to one another.

What is the process of Aeration?

Aeration is when some plants spray water into the air to remove odors and improve its taste.

What is the significance of the Hydrologic Cycle?

Because materials are constantly added to water through natural and human processes, water must continually be purified in order to be safe to use. The Hydrologic Cycle includes water-purification steps that removes potential threats to the waters drinking quality.

What is Calcium Hypochlorite, what does it look like, and where is it commonly used?

Ca(OCl)₂ is dissolved in the water. It looks like a powder and is formed as small pellets, it is often used in swimming pools, and bleaching powders.

What are carcinogens?

Carcinogens

What is chlorination?

Chlorination is the addition of chlorine to a water supply to kill harmful organisms, and its one of the most common methods of disinfection.

What is the process of Distillation?

Distillation is a process that separates liquid substances based on their differences in their boiling points.

What happens in Post-Chlorination?

During Post-Chlorination, the chlorine concentration n the water is adjusted to ensure that a low, but sufficient, concentration of chlorine remains in the water, thereby protecting the water from bacterial infestation.

What is the process of Filtration?

Filtration is the process of separating solid particles from a liquid by passing the mixture through a material that stops solid particles.

What is the process of fluoridation?

Fluoridation is when fluoride ions are added to the treated water to reduce tooth decay.

What is an example of a problem that hard water creates?

Hard water interferes with the cleaning action of soap

What happens in sand filtration?

In Sand Filtration, any remaining suspended materials that do not settle out are removed by filtering the water through sand.

What happens in filtration?

In filtration, solid particles are separated from a liquid by passing the mixture through a material that retains the solid particles and allows the liquid to pass through.

What happens in Flocculation?

In flocculation, Crystals of Alum and slaked lime are added to remove Suspended particles, such as colloidal clay, from the water. The alum and slaked lie react to form aluminum hydroxide, a sticky jellylike material that traps the suspended particles.

What happens in settling?

In settling, the aluminum hydroxide and other solids remaining in the water are allowed to settle to the tank bottom.

In water, what does chlorine kill?

In water, chlorine kills disease producing microorganisms.

How can mixtures be separated?

Mixtures can be separated by physical methods

What is Sodium Hypochlorite?

NaOCl is an aqueous solution of sodium hypochlorite is added to water.

What are three examples of water impurities that reverse osmosis removes?

Organic Compounds, Inorganic Compounds, and Microorganisms

What is the process of Reverse Osmosis?

Reverse Osmosis is a water treatment method known for removing salt from seawater, but its also used to purify drinking water by forcing untreated water molecules through a semi-permeable membrane or filter. The membrane blocks contaminants and the impurities are expelled from the environment. The result is pure, clean drinking water.

What happens in screening?

Screening is when water flows through metal screens that prevent fish, sticks, beverage containers, and other large objects from entering the water treatment plant.

What do the crystals of alum and slaked lime represent in flocculation?

Slaked Lime= Calcium Hydroxide Crystals of Alum= Aluminum Sulfate

What is the active ingredient in household bleach?

Sodium Hypochlorite

What gives water an unpleasant murky appearance in water during flocculation?

Suspended Particles

What are the six steps of Drinking Water Treatment and why do we need to do this?

The 6 steps of Drinking Water Treatment are... 1) Screening 2) Pre-Chlorination 3) Flocculation 4) Settling 5) Sand Filtration 6) Post-Chlorination We need these steps in the cleaning process to remove suspended materials, kill disease-causing organisms, and may remove odors or adjust pH levels.

What does it mean to "purify" water?

To rid the water of any contaminants

What is the single most common cause of human illness in the world?

The single most common cause of human illness in the world is unhealthy water supply.

What is water softening?

Water Softening is the process of removing calcium, magnesium, and other metal cations in hard water in exchange for sodium ions donated by a cation-exchange resin.

What is the process of pH adjustment?

Water may sometimes be acidic enough to slowly dissolve the metallic water pipes. This process not only shortens the pipes life, but may also cause copper and cadmium to enter the home water supply. Lime Calcium Oxide, a basic substance may be added to neutralize such acidic water, thus raising its pH to a proper level.

Compare what happens to soap in soft water versus hard water?

When soap mixes with soft water it disperses to form a cloudy solution topped with a sudsy layer. On the other hand, in hard water soap reacts with hard-water ions to form insoluble precipitates.