Homework #2 week two

1. The main difference between qualitative and quantitative is that qualitative tests just exhibit whether there is a presence of a substance or not while quantitative shows the amount of the substance present.
2. Confirming tests confirm that the ion in question is present.

3. A. The purpose of a reference solution is to show how the substance is supposed to react if the ion in question is present. B. The purpose of the distilled-water blank is to exhibit what a substance that does not react is supposed to look like.

4. The student should not conclude that there is no iron present because there is no possible way to disprove an ions presence with the water testing method used in the lab.

5. A. When given an unknown mixture I would determine whether it was a sollution, suspension, or colloid by trying the Tyndall effect, stirring to see if the substance changes in any way, and filtering to see if any particles are big enough to be filtered. B. The Tyndall effect shows that the substance is not a solution; if the substance is changed by stirring it cannot be a solution, and if the subsance can be filtered it is not a solution.

6. The possible risks in failing to “shake before using” are that the medicine could not be mixed properly and could not be helpful to the sick person.

7. It is useful for element symbols to be universal in science because unlike the metric system vs. the SI system there would be no conversions necessary; therefore, scientists would have an easier job distributing their discoveries universally.

8. No it is not possible for water to be 100% chemical free because the The atmospheric gases such as nitrogen, oxygen, and carbon dioxide dissolve into the water deeming it impure.

9. The physical properties of water are different from the physical properties of the elements it is made of. Water is made of 2 Hydrogen gas molecules and 1 oxygen gas molecule; these two elements are in a gaseous state at room temperature while water is in a liquid state at room temperature. Also, the freezing, boiling and liquid states of these gases are very different from water and the surface tension is less for the gases then for water.