Quick Blog Question

The solubility lab works by testing solutes in order to figure out how they react with other solvents.

Homework 6/30/13

9) 55 * +20 = 11 grams sugar

55 – 11 = 44 grams water

10)  150,000 ppm

11) A water molecule is polar because it has a negative charge (oxygen) and two positive charges (hydrogen), which attract one another.

12) 

13)

a. oxygen because it is negatively charged

b. hydrogen because it is positively charged

14) Heavy metals are called heavy because their atoms have greater masses than those of essential metallic elements; therefore, are harmful to humans and other organisms.

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

16)

a. Humans might have been exposed to lead because while lead was added to gasoline to produces a better burning automobile fuel, the lead entered the atmosphere through automobile exhaust as lead oxide.

b. Humans might have been exposed to mercury because mercury was used to make felt hats; however, hat makers suffered from mercury poisoning  after absorbing this compound through their skin.

17) Hydroxide ions (OH-) are found in many bases.

18) Hydrogen (H) is found in many acids.

19)

a. basic

b. basic

c. acidic

d. chemically neutral

20) 

a. soft drink

b. black coffee

c. milk of magnesia

21) There is a tenfold difference between units on the pH scale; therefore, a solution is 100 times more acidic at 2.0 than 4.0/

22)

Acidic: Fish egg development is impaired and the concentrations of metal ions in natural waters is increased by leaching metal ions from surrounding soil.

Basic: Dissolve organize materials, like skin and scales on fish.

23) A polar molecule is a molecule with regions of partial positive and negative charge resulting from the uneven distribution of electrical charge. An example is water; there are 2 hydrogen molecules and 1 oxygen molecule. A nonpolar molecule is a molecule that has an even distribution of electrical charge with no regions of partial positive and negative charge.

24) Since water and ethanol are both polar substances, I  would choose lamp oil because it is non polar.

25) NaCl is a polar molecule; therefore, it dissolves in water which is also a polar substance. However, oil is non polar; therefore, it does not dissolve well in water.

26) The phrase “like dissolves like,” explains the pattern of solubility behavior. Polar substances dissolve is polar solvents and non polar substances dissolve in non polar solvents.

27) Water is composed of polar molecules while grease is composed of non polar molecules; therefore, the water would not be able to dissolve the oil off the pan. In order for the grease to come off, it would have to be clean the dish with a non polar substance.

33)

a. Non polar materials are likely to be found in these cleaners.

b. These cleaners are non polar and would be able to dissolve the grease off their hands. Water is polar, therefore it would not be able to dissolve the grease.

35) If fluorine has the highest electronegativity than it has the most electrons, and is negative. Thus, hydrogen must have less electrons and has a positive charge. 

Quick Blog Question

In order to do solution concentration problems you need to know how to interpret the solubility curve graph. The tricky part is finding the percent of mass.

Homework 6/27/13

1)
a. Since you would cool the solution, it would become a supersaturated solution.
b.

2)
a and b.

ii. 25 grams of water must evaporate because some of the water has evaporated.


3)
a and b.

c. The 3b drawing has a higher water level and so the KCl is more spread out because the water is more diluted. They are both unsaturated but 3b is VERY unsaturated.

Homework 6/26/13

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. 

Quick Blog Question

I learned so much more about this lab than I initially thought I would. I learned that there are so many different types of water which react to different substances. I also realized that I can take any source of water and test it for ions.

Homework 6/25/13

25. Qualitative tests identify the presence of absence of a particular substance in a sample while a quantitative test determines the amount of a specific substance present in a sample.

26. A confirming test is a positive test that confirms that the ion is question is present. In each confirming test, you look for a change in solution color or for precipitate. 

27. 
a. The reference solution is a solution where the ion being tested for is present; therefore, it is an example of what the precipitate looks like when the ion is present in the water sample. 
b. Since the distilled-water lacks all ions, it shows that when an ion-stimulating solution is added to it, there is no reaction, but the water remains clear instead. 

28. If a student is testing a sample and the student observed no color change, there could still be ions present just in small quantities. Therefore, the student should not conclude that no ions are present. 

29. 
a. I would stir the mixture and wait for a bit to see if any particles settle on the bottom. I would also use the tyndall effect. 
b. I would stir the mixture to see if any particles are large enough to settle on the bottom because then I would know that the mixture is a suspension. I would use the tyndall effect because it would tell me that with a positive tyndall effect, the mixture is a colloid or a suspension but with a negative effect, the mixture is a solution. 

30. If one does not shake the bottle like the directions say, the large particles would stay settled in one part of the bottle and the mixture would not be uniform throughout. Therefore, the individual would not make use of the medicine because without these essential particles, the intended effect would not happen. 

31. It is useful for element symbols to have international acceptance so that scientists all around the world regard elements the same and it is easier for them to deal with these elements. 

32. 

33. Water can never be 100% chemical free, or pure. Water always contains dissolved minerals and gasses that cannot be removed. 

34. Water is made out of two hydrogen atoms and one oxygen atom. Also, water has a high surface tension but hydrogen and oxygen do not have high surface tensions. While water has a boiling point of 100 degrees celsius, a freezing point of 0 degrees celsius, and densities of 1g/ml and 1g/cm cubed, hydrogen and oxygen have different freezing points, melting points, and densities. 

water testing lab report

Nina Gabbay

Summer Chemistry

Dr. Forman

Group Lithium: Nina, Nicolette, Makena 

Water Testing Lab Report

It’s no myth, call us Lith. 

Don’t stop pour that drop, see that color change then stop. Get a table, write results, grab your group and then consult. Are there ions, are there not, it interests me a lot. 

Abstract: 

The purpose of this experiment is the test water to learn about precipitate and to detect invisible ions through the tests. Although the foul water lab only had 3 main steps, the water testing lab included four main steps: calcium ion test, iron ion test, chloride ion test, and sulfate ion test. In each test, we poured 5 different samples: the reference, the control, the tap water, the ocean water, and the distilled water. Through those steps we discovered that each water source reacted the same or differently than others after dropping ions in each substance. Ions were present in some sources, but not visible in others. 

Procedure: 

In this lab, teamwork was essential; the lab forced all group members to each take an a specific responsibility in order to accomplish our goals for the experiment. The materials we used were a beaker, wellplate, glass stirring rod, and a pipet. We decided to always make the first hole of the well the reference, the second hole the control, the third hole the tap water, the fourth hole the ocean water, and lastly, the fifth hole the distilled water. This system allowed us to stay on task and be organized throughout the whole lab. 

The first was the Calcium Ion test. We filled the first well with calcium chloride, the second with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. After adding three drops of sodium carbonate for each source of water, we found different results. The tap water and the distilled water both turned pink. However, we then observed that our results were different from everyone else; therefore, we arrived at the conclusion that the group prior to us did not clean their well. At first we were a little bothered but quickly washed the well and started over. After starting over, our results slightly differed. The reference solution (calcium chloride) became cloudy and white with precipitates, the control remained clear with no precipitate, the tap water turned unusually pink with precipitates, and the ocean water and distilled water remained clear with no precipitate. Thus, calcium ions were present in the reference and the tap water but not in the control, ocean water, or the distilled water. 

Washing the well after the different result: 

Before sodium carbonate: 

After sodium carbonate: 

The second test was the Iron Ion test. We filled the first well with ferries nitrate, the second with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. We made sure to use the one pipet for each substance so that we do not contaminate any which would change our results. After adding one to two drops of potassium thiocyanate, the results were different. The reference solution (ferris nitrate) turned from a yellow color to a deep redish black color with precipitate present. The control solution, tap water, ocean water, and distilled water all remained clear with no precipitate. Thus, iron ions were only present in the reference solution. 

Before potassium thiocyanate: 

After potassium thiocyanate: 

The third test was the Chloride Ion test. We filled the first well with calcium chloride which was the same reference solution we used for the calcium ion test. We then filled the second well with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. After adding three drops of silver nitrate, we observed that more precipitate and ions were present than the calcium ion and iron ion test. The reference solution (calcium chloride) turned from a clear substance to a cloudy and milky substance with precipitate present. The tap water and ocean water also turned cloudy and more foggy with precipitate present. The control solution and the distilled water remained clear with no precipitate present. We realized that in all the tests so far, the control solution and the distilled water remained clear with no precipitate and no ions present. Therefore, chloride ions were only visible in the reference solution, tap water, and the ocean water. 

Before silver nitrate: 

After silver nitrate: 

Our fourth and final test was the Sulfate Ion test. After each test we made sure to wash the well plate very well because we did not want our results to be different like they were the first time. So after washing the well plate, we filled the first well with ferrous sulfate, the second well with the control, the third with tap water, the fourth with ocean water, and the fifth with distilled water. After adding three drops of barium chloride, we observed the color change and precipitates present for one last time. The reference solution (ferrous sulfate) became like a milky and cloudy yellow color with precipitate present. The control solution and ocean water also became cloudy with precipitates present, but the tap water and distilled water remained clear with no precipitates. Therefore, sulfate ions were visible in the reference solution, the control solution, and the ocean water. 

Before barium chloride: 

After barium chloride: 

Results: 

Calcium Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Cloudy, precipitate present.	ions present
Control	Clear, no precipitate present.	ions absent.
Tap water	Pink, precipitate present.	ions present
Ocean water	Clear, no precipitate present.	ions absent.
Distilled water	Clear, no precipitate present.	ions absent.

Iron Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Deep red color, like blood orange, precipitate present.	ions present
Control	Clear, no precipitate present.	ions absent.
Tap water	Clear, no precipitate present.	ions absent.
Ocean water	Clear, no precipitate present.	ions absent.
Distilled water	Clear, no precipitate present.	ions absent.

Chloride Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Cloudy, precipitate present.	ions present
Control	Clear, no precipitate present.	ions absent.
Tap water	A bit cloudy, precipitate present.	ions present
Ocean water	Cloudy, precipitate present.	ions present
Distilled water	Clear, no precipitate present.	ions absent.

Sulfate Ion Test: 

Solution	Observations (color, precipitate)	Result (ions present?)
Reference	Cloudy, yellowish color, precipitate present.	ions present
Control	Cloudy, precipitate present.	ions absent.
Tap water	Clear, no precipitate present.	ions present
Ocean water	Cloudy, precipitate present.	ions present
Distilled water	Clear, no precipitate present.	ions absent.

Class results: 

For the ocean water, chloride and sulfate ions were present. But for the class, some groups had calcium ions present. 

For the control, sulfate ions were present. But for some groups, chloride and iron ions were present. 

For the reference, calcium, iron, chloride, and sulfate ions were present. 

The results for each group might have been different because each table maybe had a slight different solution which caused the results to differ.

Questions: 
1) A reference solution was used in order to see what reaction happens with a high value of the ions being tested. A blank was used to show that there is no reaction when the ion being tested for is not present in the solution.
2) Some possible problems associated with qualitative tests are that they cannot confirm ions are not  present and qualitative tests only test for the presence or absence of a substance, not the amount of the substance. 

3) These tests cannot absolutely confirm the absence of an ion because sometimes, the ion is present in such small amounts, it is not detected through the tests. 

4) If the wells are not cleaned, the results can be contaminated and therefore, incorrect data. This actually happened to our group because the group prior to ours did not clean their well plate well enough. Although the results for the first test was initially ruined, we cleaned the well plate in order to get accurate results. 

This experiment was very valuable and interesting to me. It made me realize that you can take any water sample, for example from Buckley’s turtle pond, and see what ions are present. Therefore, while initially I never thought I could test for ions myself, I then realized how simple it really is. 

Quick Blog Question

Testing water is essential for all human beings. Through water testing we can figure out what is polluting out water and by seeing what is and is not in the water, which helps prevent the spread of diseases. Without testing water, people can easily get sick and maybe even die.

Homework 6/24/13

19) 

a. 6 electrons

b. 13 protons 

c. 82 electrons

d. 17 protons 

20) 

a. no

b. no

c. yes

d. no 

21) 

a. anion

b. neutral atom 

c neutral atom 

d. cation 

e. cation 

22) 

a. gaining electrons

b. neither

c. neither

d. losing an electron

e. gaining electrons 

23) 

a. H

b. Na +

c. Cl -

d. Al ^3 +

24)

a. KI

b. CaS

c. (Fe)(Br)3

d. (Ba)(OH)2  

e. (NH4)3(PO4) 

f. (Al)2(O)3

Quick Blog Question: 

I really enjoyed the foul water lab. The oil-water separation, sand filtration, and charcoal adsorption and fitration taught me that filtering water is possible but takes lots of time. Not only did I love our first lab and the different steps, but I loved working together with my group. We especially worked well together and created a team “motto:” Started from foul now were pure. 

water diary

Per Household	Day 1	Day 2	Day 3
Number of People	6 people	6 people	6 people
Baths (number, amount of liters)	1 bath, 130 L.	0	1 bath, 130 L.
Showers (number, total time, amount of liters)	4 showers, 60 minutes total, 1,140 L.	5 showers, 80 minutes total, 1,520 L.	3 showers, 40 minutes total, 760 L.
Toilet Flushing (number, amount of liters)	14 flushes, 182 L.	13 flushes, 169 L.	10 flushes, 130 L.
Washing dishes with machine wash (number, amount of liters)	1 load, 170 L.	0	1 load, 170 L.
Washing dishes by hand (number, amount of liters)	1 time, 19 L.	1 time, 19 L.	1 time, 19 L.
Washing laundry with machine wash (number, amount of liters)	1 load, 170 L.	1 load, 170 L.	0
Use of sprinklers (number, total time, amount of liters)	1time, 1,130 L.	1time, 1,130 L.	1time, 1,130 L.
Car washes (number, amount of liters)	1wash, 680 L.	0	0
Glasses of water for cooking and drinking (number, amount of liters)	15 glasses, 3 L.	15 glasses, 3 L.	10 glasses, 1 L.
Washing indoor flowers (number, total time, amount of liters)	1 time, 5 minutes total, 90 L.	0	1 time, 5 minutes total, 90 L.
Running water in sink, number, total time, amount of liters (teeth brushing with conventional faucet)	12 teeth brushes, 2 minutes total, 38 L.	12 teeth brushes, 2 minutes total, 38 L.	10 teeth brushes, 1 minute 30 seconds total, 28 L.
Running water in sink, number, total time, amount of liters (hand washing with conventional faucet)	20 hand washes, 4 minutes total, 76 L.	18 hand washes, 3 minutes total, 57 L.	16 hand washes, 2 minutes total, 38 L.

1. Total water volume (in liters): 9,436 L 
2. Average water use per person in one day: 524.16 L 
3. The photo above. 
4. The range is 1,493. 
5. Median: 579. Mean: 600. Mean is a better representation because we have large numbers and small ones so finding the average gives a better understanding of how much water each person used per day. 
6. In our class and in Los Angeles, we have many more lawns and plants that need everyday watering. Also, since it is summer and the weather gets very warm, we need more water. 
7. My answer for question 2, 524 L, is closer to the national average, 370 L because our classes average is 524 L. 

Discussion: I have realized that the range of our class is very large; the answer for why is because some of us have larger families than others and some of us use more water for watering our yards which uses a lot of water. The average of our class is very close to my families average, which means my family does not use too much or too little water compared to all 18 of us. 

Homework 6/21/13

13. 

14.
a. i, ii, iv, and vi represent elements
b. v and iii represent compounds

15. A chemical formula represents a different chemical substance. It provides a chemical symbol which represents each element present, and a substrict which is the number written below the normal line of letters which indicates how many atoms of the element just to the left of the subscript are in one unit of the substance.

16.
a. Hydrogen (3 atoms), Phosphorus (1 atom), and  Oxygen (4 atoms)
b. Sodium (1 atom), Oxygen (1 atom), and Hydrogen (1 atom)
c. Sulfur (1 atom), and Oxygen (2 atoms)

17. 

18.
a. NaHCO3 + Hcl → NaCl + H2O + CO2
b. C6H12O6 + O6 → 6 CO2 + 6 H2O