Homework #10

#9-27, 33, 35 (p.82)

9. 55gx5= 275g

10. .015mg= 15g/l 

11. Water molecules are polar because hydrogen has a positive charge while oxygen has a negative charge. Therefor, the molecule is positive on one end and negative on the other end.

12. See model:

13. a. the oxygen end b. the hydrogen end

14. Heavy metals are called metals because their atoms have greater masses than those of essential metallic elements. 

15. Three symptoms of heavy metal poisoning are numbness, staggered walk, tunnel vision, and brain damage. 

16. Two possible sources of human exposure to led are cooking vessels and paint. Two possible human exposures to mercury are by thermometers and fluorescent light bulbs. 

17. Hydrogen is in many base ions. 

18. Hydrogen is used in many acids.

19. a. seawater: basic, b. drain cleaner: basic, c. vinegar: acid, d. pure water: chemically neutral

20. a. Soft drinks, b. black coffee, c. milk of magnesia

21. two times more acidic

22. Three negative effects of inappropriate pH levels on aquatic organisms are impaired fish egg development, increased concentration of metal ions,  and dissolved organic materials. 

23. Polar molecules are molecules that have a negative charge on one end and a positive charge on the other end. Non polar molecules only have one charge. In addition, polar molecules have a V shape.

24. I would select lamp oil because it is also non polar.

25. This is because it is polar.

26. This means that polar substances dissolve in polar substances while non polar substances dissolve in non polar substances.

27. This is because the oil will not dissolve in water.

33. a. there are most likely non polar substances in the cleaner b. they are more effective because the oil will dissolve in the non polar cleaner and will remove the oil.

35. Hydrogen would have the positive charge because fluorine has a negative charge and it would need to bond together. 

Blog Question

Do to solution concentration problems you must understand how to read the graph. The hardest part is understanding how to figure out the percent of mass.

Homework #9

#1-3 (p.62)

1. a. It would become a super saturated solution because you would be cooling a saturated solution. b. See Model:
2. a. See Model: b. 25 g must evaporate
3. a. B is less saturated then A.
4. 

Homework #8

Pg. 56

1)
a. 105 KNO3
b. 44 KCl

2)
a. 20 grams of potassium nitrate must be added to form a saturated solution at 20 degrees Celsius
b. 45 grams is the minimum mass needed to dissolve 25 g potassium nitrate

3)
a. 60 grams of potassium nitrate will precipitate.
b. 110 will have to be added to dissolve all of the KNO3.


pg. 82

1) As the temperature of water increases, the solute dissolves easier. Since tea has a higher temperature than iced tea, the three teaspoons of sugar will completely dissolve.

2) The maximum mass that will dissolve is 48 grams.

3)
a. 200 grams
b. 710 grams
c. 1,892 grams

4)
a. NaCl, KCl, KNO3.
b. KNO3, KCl, NaCl.

5) A saturated solution is a solution in which the solvent contains as much dissolved solute that it can hold at a specific temperature. A unsaturated solution is a solution that contains less dissolved solute than the amount the solute can hold at a specific temperature. 

6)
a. 30 grams
b. Saturated
c. 90 grams should form.

7)
a. If the solution is unsaturated, it will dissolve.
b. If the solution is saturated, it will become rebalanced.
c. If the solution is supersaturated the crystal will sink to the bottom.

8) If you have 115 grams of water
35/115+35 = 23% et by mass. 

Water Testing Lab Report



WATER TESTING LAB

June 25, 2013

Abby, Jilly, Layla

Chemistry

Dr. Forman

Abstract:

   The purpose of the lab was to learn how to test various substances for ions. We tested distilled water, a reference solution, an unknown solution, tap water, and ocean water for calcium, iron, chloride, and sulfate ions. The distilled water was our blank well, in which we were to expect no precipitate. Our reference solutions were used to know what a precipitate would look like. If the substance changed when we added the chemicals then a precipitate would form and we could conclude that the ion was present. If the substance didn't create a precipitate then we would conclude that there were no ions present. This lab tested our teams' carefulness and we had to pay close attention to directions. In addition, we had to be extremely careful to not cross contaminate chemicals as that could cause false results. 

Procedure:

1. Preparation
1. be sure to clean all equipment before and throughout the lab
2. put on gloves and other safety equipment
3. Gather all of the chemicals 
2. Calcium Ion Test



1. Put 20 drops of each of the following into individual wells and label: distilled-water blank, calcium reference, unknown, tap water, and ocean or natural water. 
2. Add three drops of the sodium carbonate test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that there was no ion present in the unknown substance
6. Wash the well plate, rod, and pipette with distilled water
3. Iron Ion Test

1. Put 20 drops of each of the following into individual wells and label: distilled-water blank, Iron reference, unknown, tap water, and ocean or natural water. 
2. Add one or two drops of the potassium thiocyanate test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that there was no ion present in the unknown substance
6. Wash the well plate, rod, and pipette with distilled water
4. Chloride Ion Test
1. Put 20 drops of each of the following into individual wells and label: distilled-water blank,Chloride reference, unknown, tap water, and ocean or natural water. 
2. Add three drops of the Silver Nitrate test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that there was no ion present in the unknown substance but there was in the tap and ocean water
6. Wash the well plate, rod, and pipette with distilled water
5. Sulfate Ion Test
1. Put 20 drops of each of the following into individual wells and label: distilled-water blank, sulfate reference, unknown, tap water, and ocean or natural water. 
2. Add three drops of the barium chloride test solution to each of the wells. You should see no change in the coloring of the distilled-water well but you should see a reaction in the solution well. If these results are not the case make sure you are doing the procedure correctly. 
3. Stir with the glass rod being careful to wash and dry the rod after each well
4. Record results of the coloration in a table: 
5. We concluded that the ion was present in the all of the substances except for the tap and distilled water
6. Wash the well plate, rod, and pipette with distilled water

Results:

1. There was a reference solution to see what an ion being present would look like while a blank is to see what a solution that doesn't create a precipitate looks like. 
2. The possible problems associated with qualitative tests are that there can be differing answers. 
3. The tests cannot completely confirm the absence of an ion because there could be such a small amount of an ion in a liquid that it doesn't change the appearance of the solution.
4. The observations may have changed if we hadn't properly cleaned the rod because we may have contaminated the wells to show false ions present.

Significance/ Results Discussion:

   We confirmed that the unknown solution had sulfate ions present. Our group had a differing conclusion as to if the control had calcium in it. We concluded that the control didn't have calcium while other groups concluded that it did have calcium. A possible reasons why it could be different are because we may have had a different control solution then the other ones in the class. Other possibilities include contamination or not properly reading chemicals. Because these are qualitative tests the interpretation of a precipitate could be different. 

Class Data:

Blog Question

I learned how to test water for ions of different elements in water. In addition, I learned that there are many different elements in water that I didn't know about. Distilled water is the most pure out of the waters we tested for.

Homework #7

#25-34 (p. 51-52)

25. Qualitative tests require observation of appearance such as making note of color, while quantitative tests measure the amount of a substance.

26. Confirming tests are tests that confirms that the ion in question is present.

27. The purpose of the reference solution was to see what the formation of precipitate looked like, while the distilled-water blank well was to see what a non reacting well looked like.

28. The student cannot conclude that there is no iron present. The reason it appears to not be present is because there may only be a small amount of iron in the water.

29. I would let the mixture sit for a while and see if any particles settle or if there is a visible suspension. Then I would try the Tyndall test and see the result. If there are visible particles or layers of different liquids appear then it is a suspension. If you try the Tyndall effect but there are no particles visible it may be a colloid. If the previous tests are inconclusive, then it may be a solution.

30. The possible risks of not shaking a medicine bottle if it indicates to do so are that you get only one part of the medicine. In other words, if the medicine is in suspension and you take a sample, you won't get an evenly distributed solution of medicine ingredients.

31. It is useful for element symbols to have international acceptance so that scientists all over the world don't get confused as to the properties or characteristics of an element.

32. See Picture:

33. It isn't possible for water to be 100% free of chemicals. M
inerals will always be in water.

34. Water is composed of two hydrogen atoms and one oxygen atom. It is also polar and has surface tension. Waters' boiling point is 212 degrees F and its freezing point is 32 degrees F. The physical properties of the elements that compose water do not have those properties.

Homework #6

#19-24 (p. 51)

19. a. Carbon: 6 protons and 6 electrons
      b. Aluminum: 13 protons and 13 electrons
      c. Lead: 82 protons and 82 electrons
      d. Chlorine: 17 protons and 17 electrons
20. a. Sulfer- not neutral
      b. Iron: not neutral
      c. Silver: Neutral
      d. Iodine: not neutral
21. a. anion, b. neutral, c. neutral, d. cation, e. cation
22. a. gaining electrons, b. neither, c. neither, d. loosing electrons, e.  loosing electrons
23. a. H, b. Na+, c. Ch-, d. Al+
24. a. KI - potassium iodine, b. CaS - calcium sulfur, c. FeBr - iron bromine, d. BaOH - barium oxygen hydrogen, e. NHPO - nitrogen hydrogen phosphorous oxygen, f. AlO - aluminum oxygen

Homework #5

#1-7 (p. 20-21)

1. Throughout the three days we used 14,831L of water.
2. One member of my family used on average 1,853.88 L of water per day.
3. See histogram:

4. The range of the average daily personal water use from 360L-1853L. That is a 1,493L range.
5. The class average was 600L and the median was 579L.
6. Due to watering yards year round and because we live in a dessert, we use more water than the daily average.
7. The class average is closer because we all have different size yards and varying uses for water.

#12-18 (p. 50)

13. See drawing:
14. (i), (ii), and (vi) are represent elements. (iii), (iv), and (v) represent compounds.
15. Chemical formulas represent the elements present and the subscript.
16. Three Hydrogen, one Phosphorus, and four Oxygen. One Sodium, one oxygen, and one hydrogen.     One sulfur,  and two oxygen.
17. See drawing:
18. Chemical equations:

• Na9 HCO3 + HCl -> NaCl + H2O + CO2

• C6 H12 O6 + O6 -> CO6 3 H2O

Discussion Question:

The value of reading about science is to realize that it is relevant and all around us. Often, we can think that science, specifically chemistry, is something we won't use when we are older unless we become a scientist. Reading about current events in science shows us how much it applies to our lives.

Homework #4

Homework #3 - #1-3 p.33

1. Homogeneous mixture composed of three elements

2. This model represents a heterogeneous suspension because we can see the two layers created.

3. Samples of matter

Homework #3

ISBS: #1-12 (p.50)

1. Physical properties are properties that can be  observed and measured without changing the chemical makeup of the substance. 
2. The physical properties of water are density, freezing point, and boiling point. 
3. The density of liquid water is more than the density of solid water (ice). This is why ice floats to the top of water. 
4. A setting where you could observe water as a liquid, gas, and solid would be if you were at the beach. You may be sipping some ice water, watching the waves, and think about the water that is evaporating into water vapor because it is very hot outside. 
5. A heterogeneous mixture is a mixture that is not uniform throughout, while homogeneous mixtures are uniform throughout. 
6. To predict what liquid will be on top you need to know the two water densities. Because gasoline is a type of oil, we can conclude that the gasoline will sit on top of the water. 
7. Solution, Suspension, or Colloid?
1. Suspension
2. Suspension
3. Colloid
4. Solution
5. Suspension
6. Colloid
8. This demonstrates a solution because there are no particles disturbing the light beams
9. See drawing below
10. This red mixture would be a solution because it is a homogeneous mixture do to the fact that it didn't have any particles settle over time. In other words, the mixture was uniform throughout. 
11. A substance is an element or compound with uniform and definite compositions, as well as distinct properties. 
12. Element or Compound
1. CO - Compound
2. Co - Element
3. HCl - Compound
4. Mg - Element
5. NaHCO3 - Compound
6. NO - Compound
7. I2 - Compound

#9's drawings 

Terms - 1A Vocab

1A Terms List

purity: free from impurities

filteration: solid particles separated from a liquid by passing the mixture through a material that retains the solid particles and allows the liquid to pass through

filtrate: the liquid collected after it has been filtered 

adsorb: to attract and hold onto a surface.

percent recovery: percent of original foul water sample recovered as purified water.

purified water: water that has been cleaned through a process of filtration/purification. The final step of purification is distillation.

histogram: shows percent recovery obtained (by all laboratory groups in the class).

range: the difference between the largest and smallest values in a data set.

average/mean: average value found by adding all values together and dividing the sum by the total number of values.

median: middle value

distillation: the process of separating salt from water through evaporation and condensation in a distillation apparatus.

electrical conductivity:  the presence of dissolved, electrically charged particles in water.

Tyndall Effect: the clarity of a water sample tested by passing a beam of light through each sample. 

water cycle/hydrologic cycle: the cycle of water falling, evaporating into the air, condensing, and falling again.

direct water use: water that can be directly measured.

indirect water use: hidden uses of water.

gaseous state: water vapor in the air.

liquid state: in lakes, rivers, oceans, clouds, and rain.

solid state: ice.

surface water: a river or other body of water.

groundwater: a well- must be pumped to the surface.

aquifer: a water-bearing layer of rock, sand, or gravel.

How the Periodic Table Works

The periodic table is made up of elements that are organized based on their atomic numbers. The number on the top left of the element is called the Atomic Number. The element symbol is the letter(s) in the middle of the element box on the table. The Atomic mass is at the bottom of the element box. The table consists of groups and periods.The color of the  atomic number shows if an element is a  liquid, gas, solid, or unknown. Groups run vertically while Rows, or periods, go from left to right. Elements that have similar properties are in groups.