Download Sc8 - a 2.3 (student notes)

Science 8
Mix and flow of matter
Learning outcomes:
1 Identify factors that affect solubility and rate of dissolving
2.3 – Factors Affecting Solubility
Water –
 is called the ____________________
o Because it can dissolve so many materials.
 The term’ ______________ ‘means water.
 The term ‘_____________________ means _____________________
o 97% of the water on Earth is
Ocean water, 2% is frozen and
only about 0.5% is 'usable' (and
even this has materials already
dissolved in it that can be
harmful),
 Solutions are not only made up of
liquids. The chart on p. 29 illustrates
other mixtures that can make solutions.
 ________________________ as the temperature of the
________________________, because more space is provided between
the particles for the solute particles to fit (dissolve) into.
Science 8
Mix and flow of matter
 The reverse is __________________________ - as the
__________________________, the solubility of a gas, in a liquid
solvent decreases.
This decrease in the solubility of
gases can have a serious effect on
the environment. If the temperature
of water increases (warm industrial
waste water poured directly into
lakes and rivers) then there is less
oxygen that can be dissolved in the
water – thus, affecting the living
organisms in the water. This is called thermal pollution.
Questions:
1. Why water is called “the universal solvent?”
2. What factors affect the solubility of a solute?
3. Answer question #3 from page 31. (a b and c)
a. Which substance is most soluble at 100 degrees Celsius?
b. Which substance is most soluble at 0 degrees Celsius?
c. Which substance shows the most change in solubility as the temperature
increases?