Water quiz! (Chemistry C3)

There are two types of hard water. Temporary and permanent, true or false?

The hardness of water is caused by [blank_start]CA2+[blank_end] ions and [blank_start]Mg2+[blank_end] ions. Hard water contains a massive amount of [blank_start]calcium[blank_end] and [blank_start]magnesium[blank_end] ions. These are added to the water when rain falls onto rocks such as [blank_start]limestone[blank_end]. Compounds in the rocks such as [blank_start]magnesium sulphate[blank_end] and [blank_start]calcium sulphate[blank_end] are [blank_start]dissolved[blank_end] into the water.

Select an advantage of hard water.

Rainwater is an [blank_start]acidic[blank_end] solution which [blank_start]reacts[blank_end] with limestone. The solution formed in the lake is known as [blank_start]hard water[blank_end]. One advantage of drinking the water from the lake is that it [blank_start]tastes[blank_end] better than rainwater.

what is the name of the process used to remove solid particles from water to make it safe to drink.

Fluoride is added to the water to sterilise it.

An [blank_start]ion exchange column[blank_end] is used to soften hard water. The column contains [blank_start]sodium ions[blank_end] which are positively charged. However, calcium and magnesium ions have a [blank_start]greater charge[blank_end] and therefore [blank_start]displace[blank_end] the sodium ions. The sodium is soluable so it will then [blank_start]dissolve[blank_end] into the water.