Chemistry Homework #7

Pg 51-52 #25-34


25. QUALITATIVE: tests that identify the presence or absence of particular substance in a sample.
QUANTITATIVE: test that determine the amount of a specific substance present in the sample.


26. CONFIRMING TEST: if a positive test confirms that the ion in question is present.


27. A. The purpose of the reference solution was to see an example of what the ion in question would look like.
B. the purpose of a distilled water blank was to see an example of what a sample would exemplify if there were no ions in it.


28. No, because there could be iron ions in it, but there are not enough, or they are not large enough to be seen when the solution is put in.


29. A. By looking to see if there are particles within the water. If there are, then you must see if the particles within the water fall to the bottom or stay floating throughout.
B. If there are visible particles in the water, it shows that it is not a solution because the particles are not homogeneous with the atoms of the water. By looking at the visible particles, you can decide whether or not the particles would be considered big enough to be filtered out with one of the three methods used in the lab, or if they sink to the bottom after sitting for a little while.


30. The possible risks of not following the directions is that the important ingredients that could help to heal or make you feel better could be within the particles that sank to the bottom and so the medicine will not work to its full extent because you don’t get the important parts in the medicine.


31. It is useful for element symbols to have international acceptance because it lets scientists from all over the world be able to understand what another is talking about as well as providing unification within the science world.


32.

33. No, it is not possible to have water that is 100% chemical free because even though water is pure, it gets exposed to the oxygen and other gases in the air even before it get packaged, so it is no possible.


34. A physical property of water is its surface tension because it is a polar molecule with one positively charged and one negatively charged end. The property of Hydrogen is that it is positively charged, while oxygen is negatively charged, therefore, when bonded together in a water molecule, retain their original properties and give them to water.