According to the diagram, what is the boiling point of water at sea level?

Between 4°C and 99°C, how much does water expand according to the diagram?

When water freezes, what change in volume is shown on the diagram?

When water exceeds 100°C and turns to steam, by approximately how much does it expand compared with its original volume?

Up to 100°C, how does heated water typically behave in a closed system at cold start?

What is the chemical formula of water?

The slide states that pure water is rare because water is a very powerful what?

Given enough time, which actions will water perform on materials according to the slide? Select all that apply.

Depending on where water collects, what will it absorb and contain according to the slide?

Which characteristics can absorbed substances give to water according to the slide? Select all that apply.

Based on the diagram of rainwater falling through different ground conditions, which ground type leads to temporary hard water (alkaline)?

Temporary hard water, when heated above 65°C, forms which deposit that causes problems for appliances?

According to the material, what effect does limescale have on appliances?

From the diagram, which waters are identified as acidic? Select all that apply.

Hardness in water is referred to as which factor affecting soap use?

Which compounds are primarily responsible for permanent hardness in water?

What is the stated method for removing temporary hardness from water?

Permanent hardness can only be removed by which method mentioned?

When temporary hardness is removed, what is released according to the notes?

According to the statement on total hardness, what contributes to the total hardness of water?

On the pH scale shown, what value is neutral?

Which pH range is indicated as alkaline on the depicted scale?

What effect is associated with acidic water in the illustration?

Water that has the ability to dissolve lead is called what?

Water that is aggressive towards copper is called what?

In unprotected areas, water rapidly forms which substance on ferrous (iron) metals?

How should iron pipework be protected according to the guidance?

Ferrous oxide buildup inside radiators results in which maintenance action?

What can be used to protect central heating pipework and components?

Which definition describes evaporation?

Which definition describes freezing?

Which definition describes condensation?

Capillary action of water is when water can be drawn sideways or upwards between two close-fitting surfaces against gravity. Which statement best describes this?

According to the statement "The wider the gap, the less capillary action there is," what happens to capillary action as the gap between two close-fitting surfaces increases?

In the diagram showing three vertical tubes of different diameters standing in water, which tube displays the greatest capillary action (highest rise of water)?

Capillary action of water causes water to be drawn up underneath lead weathering on tiles, resulting in leakage inside the property. Which measure is most effective to overcome this problem by breaking the capillary path at the flashing-to-tile interface?

Water can be drawn up between lead weathering surfaces by capillary action. Which detailing best prevents this by introducing an anti-capillary feature within the joint?

Capillary action can contribute to loss of trap seal in an S trap under an appliance. What is the most appropriate measure to minimise seal loss and maintain the water seal?

Capillary action of water — Conversely plumbers can use this to their advantage: To make soldered joints on fittings, the solder can be drawn between the two close‑fitting surfaces of the copper tube and fitting. Which phenomenon enables solder to be drawn into the joint between the copper tube and fitting?

Capillary action of water — Conversely plumbers can use this to their advantage: To make soldered joints on fittings, the solder can be drawn between the two close‑fitting surfaces of the copper tube and fitting. Between which surfaces is the solder drawn when making the joint?

Properties of water — The water molecules have a cohesive nature in the way they stick together. This creates the surface tension on top of water. Which property of water is responsible for surface tension?

Properties of water — The water molecules also have an adhesive nature and tend to stick to other materials they come into contact with. This gives the water a curved appearance. What name is given to the curved surface formed by water due to adhesion?

Properties of water — In a manometer, we have to read the water level from the bottom of the meniscus or curve. Where should the water level be read in a manometer?

Solid (ice) – liquid (water) – gas (steam). What is the chemical symbol for water?

Boiling point of water = $$100^\circ\mathrm{C}$$ (at sea level). What is the boiling point of water at sea level?

Increase the pressure = increase the boiling point of water. What effect does increasing pressure have on the boiling point of water?

When boiling it expands by = 1,600 times. By approximately how many times does water expand when it boils to form steam?

Maximum density of water = $$4^\circ\mathrm{C}$$ . At what temperature is the density of water at its maximum?

Water freezes at = $$0^\circ\mathrm{C}$$ or $$273^\mathrm{K}$$ . At which temperature does pure water freeze?

Add glycol (antifreeze) to water = reduces freezing point. What is the effect of adding glycol (antifreeze) to water?

When frozen, water expands by = 10%. Approximately how much does water expand when it freezes?

Relative density of water = 1. What is the relative density of water taken as?

Water heating from $$10$$ – $$90^\circ\mathrm{C}$$ expands by = 4%. Approximately how much does water expand when heated from $$10^\circ\mathrm{C}$$ to $$90^\circ\mathrm{C}$$ ?

Sensible heat — When heat is applied to water the temperature will rise, but it remains water. It can then be cooled (a change in temperature without a change in state). Which term describes heat that raises the temperature of water without changing its state?

Latent heat — If you keep heating water, it will change from water to steam; this is a change in state. Which term describes the heat required to keep water boiling (change of state)?

Water softener — The only way to fully remove hard water and prevent scale, scum and tide marks is to fit a water softener. What is fitted to fully remove hard water and prevent scale, scum and tide marks?

Water softener — Water is taken through a zeolite or resin bed then flows out of the top of the vessel to the tap. The resin holds the calcium and magnesium in the filter. Which ions are held by the resin in a water softener?

Water softener — The unit is then back‑washed by a brine solution (salt or sodium chloride). What solution is used to back‑wash a water softener unit?

Chemicals used for scale control in domestic systems do not soften the water; they stabilise salts to prevent scale forming. Based on the description, what is the primary role of polyphosphate chemicals on salt crystals?

According to the description, are the chemicals used for scale control considered water softeners?

Where are the described chemical scale treatments commonly used?

In a magnetic scale inhibitor, water passes through a strong magnetic field running across the flow. What effect does this have on the salt crystals?

What is altered by the magnetic scale inhibitor as water flows through the magnetic field?

An electrical scale inhibitor works similarly to the magnetic type but uses a magnetic field to produce low-level radio waves that pass through the water. What distinguishes the electrical inhibitor from the purely magnetic one?

In the illustrated electrical scale inhibitor setup, which component provides energy to the electronic enclosure that drives the wrapped wires around the pipe?