We propose an experimental activity that will allow you to do something similar to what is done in the salt flats. Suppose you have a mixture of salt and chalk and you want to separate its phases. Can you think of how to do it? Materials: pieces of chalk, coarse or fine salt, water, a transparent heat-resistant container, a spoon, a heat source (lighter or heater). Solution: Mix equal amounts of salt and chalk in the container. In this way, you will have obtained the heterogeneous system with which you are going to work. Add water and stir with the spoon. Let stand. a) What happened? b) How do you explain what you observed? Two processes have occurred: the dissolution of the salt and the sedimentation of the chalk. Both the chalk and the salt are still present, only the salt is not visible because it is dissolved in the water. The identity of each of the materials was not affected: we say that physical changes have occurred in the system. The materials that constituted the initial heterogeneous system have different properties. in particular the solubility in water and this difference is what allowed us to carry out a first separation. Let's go a little further: now it's about separating the chalk from the salt water. c) How to do it? You could try it by any of these methods:
We propose an experimental activity that will allow you to do something similar to what is done in the salt flats. Suppose you have a mixture of salt and chalk and you want to separate its phases. Can you think of how to do it? Materials: pieces of chalk, coarse or fine salt, water, a transparent heat-resistant container, a spoon, a heat source (lighter or heater).
Solution: Mix equal amounts of salt and chalk in the container. In this way, you will have obtained the heterogeneous system with which you are going to work. Add water and stir with the spoon. Let stand.
a) What happened?
b) How do you explain what you observed?
Two processes have occurred:
the dissolution of the salt and the sedimentation of the chalk.
Both the chalk and the salt are still present, only the salt is not visible because it is dissolved in the water. The identity of each of the materials was not affected: we say that physical changes have occurred in the system. The materials that constituted the initial heterogeneous system have different properties. in particular the solubility in water and this difference is what allowed us to carry out a first separation. Let's go a little further: now it's about separating the chalk from the salt water.
c) How to do it? You could try it by any of these methods:
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