Page 48 - Curriculum Visions Dynamic Book

When carbon dioxide dissolves in water, it produces another weak acid – carbonic acid – but again it has only fair conducting properties.
The properties of dissociation can be used to great effect, for example, in the industrial separation of salt from salt water (see pages 50 to 51).
Introducing medicines to the blood
Blood (which doctors regard as an electrolyte) is water containing a huge array of other substances, one of which (hemoglobin) colours the water red. But there are many others, and they are all important in carrying vital nutrients and other substances to the cells of our bodies.
One important result of this is when people are ill and need extra supplies of vital substances. They are introduced into the blood using an intravenous drip, that is, the water containing the substances needed to help life are fed in through a needle directly into the blood supply.
Pills are the same. They contain substances that dissolve and so enter the blood supply, where they can be carried to the cells that need the chemicals the pills contain.
(Above and left) The effect of impurities on the boiling point of water. When some salt is added to water, a stirring thermometer shows an increase in boiling temperature. In this case it shows 105.5°C. Increasing the amount of salt further increases the boiling point.
(Left) Because the body is essentially a hugely complex chemical factory whose transportation system is
water, the method for getting nourishment and drugs (medicines) to the body quickly in times of illness is to take them orally (when they dissolve in the stomach) or intravenously (when they enter the bloodstream directly).
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