Water Chemistry Quiz

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Questions and Answers

What is the boiling point of water at sea level?

100 degrees Celsius (correct)

50 degrees Celsius

0 degrees Celsius

200 degrees Celsius

At what temperature does water have its maximum density?

0 degrees Celsius

100 degrees Celsius

25 degrees Celsius

4 degrees Celsius (correct)

How much does water expand when it freezes?

20%

10% (correct)

15%

What happens to temporary hard water when heated above 65°C?

It forms limescale Signup and view all the answers

What type of hardness in water can be removed by a base exchange method?

Permanent hardness Signup and view all the answers

By how much does water expand when converted to steam?

What common issue arises from hard water in appliances?

Formation of limescale Signup and view all the answers

What effect does heating water from 4°C to 99°C have on its volume?

Increases by 4% Signup and view all the answers

What role does zinc play in a galvanic cell?

It is the anode that breaks down. Signup and view all the answers

What is temporary hardness in water?

Hardness caused by dissolved minerals that can be removed by boiling. Signup and view all the answers

What effect does limescale have on plumbing systems?

It blocks pipes and components. Signup and view all the answers

What is the measurement used to define hard water?

Parts per million Signup and view all the answers

If water is heated to 100 degrees Celsius and changes to steam, what type of heat is this process classified as?

Latent heat. Signup and view all the answers

At what pH level is water considered neutral?

7 Signup and view all the answers

Which pH scale range classifies water as acidic?

1-6. Signup and view all the answers

Which term refers to water's ability to dissolve lead?

Plumbosolvent Signup and view all the answers

Which chemical method can be used to protect iron pipework from corrosion?

Red oxide paint Signup and view all the answers

What occurs when a gas turns into a liquid?

Condensation Signup and view all the answers

How does capillary action of water primarily function?

By drawing water sideways or upwards against gravity Signup and view all the answers

What is a common result of ferrous oxide buildup in central heating systems?

Need to bleed radiators Signup and view all the answers

Which property of water creates surface tension?

Cohesive nature of water molecules Signup and view all the answers

What is the boiling point of water at sea level in Celsius?

100 C Signup and view all the answers

What effect does increasing pressure have on the boiling point of water?

Increases it Signup and view all the answers

What happens to water when it freezes?

It expands by 10% Signup and view all the answers

What is the term for the heat required to keep water boiling?

Latent heat Signup and view all the answers

What component in water softeners holds calcium and magnesium?

Zeolite or resin bed Signup and view all the answers

How do chemicals like polyphosphate stabilize salts in water?

By preventing crystals from forming Signup and view all the answers

What is the operational principle of a magnetic scale inhibitor?

Breaks salt crystals into smaller pieces Signup and view all the answers

Study Notes

Scientific Properties and Principles of Water

Water is a chemical compound of hydrogen and oxygen (H₂O).
Pure water is rare; it's a powerful solvent.
Over time, water can erode, corrode, and absorb various substances depending on its environment.
This absorption gives water characteristics like hardness, softness, acidity, and alkalinity.
The water cycle involves evaporation, transpiration, condensation, and precipitation.
Hard water contains minerals like calcium and magnesium.
Temporary hard water contains calcium carbonates which can be removed by heating the water above 65°C . This creates limescale.
Permanent hard water contains calcium sulfates; it requires a base exchange method (e.g., a water softener) to remove.
Hardness in water is measured in parts per million (PPM). Over 200 PPM typically requires treatment.
Water's acidity or alkalinity is measured using the pH scale.
Pure water has a neutral pH of 7; between 1-6 it is acidic; and 8-14 is alkaline.
Water expands as it is heated up to 100°C; the expansion is usually up to 4% from 4°C to 99°C.
Water expands approximately 1,600 times its original volume upon boiling to form steam.
Water expands by approximately 10% when it freezes.
Water's maximum density is at 4°C.
The boiling point of pure water is 100°C at sea level.
Adding antifreeze (glycol) reduces the freezing point of water.
Water exhibits capillary action; it can be drawn upward or sideways against gravity between close-fitting surfaces. This action is affected by the size of the gap (or width.)
Water's cohesive nature creates surface tension.
Water's adhesive nature causes water to stick to other materials leading to a curved appearance (meniscus) for example in a manometer.
Plumbers consider capillary action as a problem in plumbing (e.g., leaks inside or loss to an appliance). Conversely, plumbers use capillary action to their advantage (e.g., creating soldered joints).

Quick Fire Questions

Boiling point of water = 100°C
Water has maximum density at 4°C
Water expands 4% from 4°C to 99°C
Steam expansion = 1,600 times
Water expansion when freezing = 10%

Types of Heat

Sensible heat: When heat is added to water, its temperature increases without changing state.
Latent heat: When heat is added to water; it causes a change of state, like changing from liquid to gas.

Water Treatment Methods

Water Softener: Removes hard water minerals like calcium and magnesium through zeolite or resin beds; the softening unit uses a brine solution to clean and maintain the resin beds.
Chemicals or Polyphosphates: Stabilize minerals to stop hard scale formation, preventing mineral crystals from bonding.
Magnetic Scale Inhibitor: Passes water through a strong magnetic field to change the salt crystals, preventing sticking and scale formation.
Electrical Scale Inhibitor: Uses low-level radio waves produced by a magnetic field to alter salt crystals preventing scale formation.
Galvanic Cell Scale Inhibitor: Uses a combination of zinc and copper to develop an electron flow to break down scale buildup in appliances or systems.

Lesson Intent

Students will learn to identify different types of water.
Students will be able to describe water properties in different states.
Students will be able to compare temporary and permanent hard water.

Types of Hardness

Temporary hardness: Dissolved calcium carbonate. Removing the minerals requires heating the water.
Permanent hardness: Dissolved calcium sulfate, removing this requires alternative methods like a water softener.

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Description

Test your knowledge on the properties and characteristics of water, including its boiling point, density, and hardness. This quiz covers various chemical concepts related to water, making it essential for students of chemistry and environmental science.