Good Science Victorian Curriculum Year 7

CHEMICAL SCIENCES
5.3
WATER AS A
SOLVENT
LEARNING INTENTION
At the end of this lesson I will be
able to describe the importance
of water as the universal solvent.
LITERACY LINK
WRITING
Write a postcard to a friend
about your trip to a country with
very limited access to water.
NUMERACY LINK
UNITS
1 cm 3 of water weighs exactly 1 g.
How many cubic centimetres
would 1.5 kg of water take up?
1
Water is vital for life on Earth – without water we couldn’t
survive. Our bodies need water, and so do the plants that we
eat. We also need water for daily activities such as cooking
and washing.
Water is a solvent that can dissolve other substances.
We use it to extract minerals from underground and to make
medicines. Water is known as the universal solvent because
it dissolves more substances than any other liquid.
Water is a solvent in daily life
A solvent is any substance, usually a liquid, that can dissolve other
substances.
Water is a solvent, and it can dissolve many other substances –
solids, liquids and gases. When these substances dissolve, they are
called solutes. Water acts as a solvent in daily life in many ways.
• Human survival: Water is an essential solvent for humans. Blood is
mostly water, and it carries nutrients and oxygen throughout our
bodies.
• Preparing meals: Water dissolves spices, flavours and other
ingredients as food cooks.
• Washing away dirt: Water acts as a solvent
for soaps and detergents when cleaning
dishes, clothes and ourselves.
How does water act as
a solvent?
Figure 5.5 Water is a solvent for
important minerals in our bodies.
When we do intense exercise, we
lose water and minerals dissolved
in our sweat.
72 GOOD SCIENCE VICTORIAN CURRICULUM 7