Solubility Rules Lab

Due Today: Micro Mole Rockets Lab
                    Solubility Curve Practice Problems
                    Dissocations Worksheet
Due Tomorrow: Nothing :)

Today, we started class by going over the Solubility Curve and Dissocations sheets. Then we started the Solubility Rules Lab. We had to test 6 different sodium, or anion, solutions (sodium carbonate, sodium chloride, sodium hydroxide, sodium iodide, sodium phosphate, and sodium sulfate) with 8 diffferent nitrate, or cation, solutions (aluminum nitrate, potassium nitrate, barium nitrate, calcium nitrate, copper (II) nitrate, iron (III) nitrate, silver nitrate, and zinc nitrate). We put 4-5 drops of each solution into two trays, which make a 6x8 grid. On our data table, we had to label the 6x8 grid that was given to us. The anion solutions ran each row, the cation solutions each column.

When we tested, we put a couple drops of each solution to see if there was any color change and/or cloudiness.

Lab Goal: To determine the solubility rules for ionic compounds by testing for precipitates.

Data: A 6x8 chart to record if precipitate formed for each solution mix

Claim: Which anion testing solution made the fewest precipitates? The most precipitates?

Evidence: Cite evidence to support your claim

Reasoning: Although you did not test the bromide anion, would you expect most bromide salts to be soluble or insoluble? Site data to support your answer.

Homework: Lab due Friday

Happy Halloween!!

Next Scribe: Daniel H

Formula of a Nitrate Lab

Homework:
-Due today: Gram to Gram Stoich
-Due tomorrow: Intro to Limiting Reactants
-Due Monday: Formula of a Nitrate Lab

We started day #1 of the formula of a nitrate lab. By doing this lab we can use the masses of the reactants and products to calculate the number of moles of copper used and silver produced.

Lab goal: To determine the formula of the nitrated silver which ion of copper formed (the +2 ion or the +3 ion).

Procedure:
1. Place 1.5g of silver nitrate and 25ml of water in either a 50ml beaker or a 100ml beaker.
2. Stir the solution until all the silver nitrate has dissolved.
3. Cut a 25cm piece of copper wire. Then loosely coil the wire and record its mass in a data table. Use the wooden split to to let the copper wire hang into the silver nitrate solution. Add 3 drops of nitric acid.

-We had to wait 15 minutes for this to happen. While we waited though we took the stoich quizzes #2 and #3. You took #2 if you weren't here yesterday, and you took #3 if you were.

4.  Clean and label 100ml beaker and record the mass.
5.  After the 15min. we removed the wire and held above the clean
100ml beaker, while steadily rinsing off the silver. Then clean off the wire in another beaker with acetone.
6. Measure/record the copper wire.
7. Carefully pour the water from the beaker full of silver into the waste flask. Don't pour out the silver!
8. Allow the solid to dry over night and record the mass of the beaker.

-Each group placed their beaker on a tray for drying, and that concluded day #1 of the lab. We will continue the lab tomorrow. Don't forget it's due on Monday!

NEXT SCRIBE: Renee H.

Stoich1

Monday 15, 2012 BLOG
-Georgia K-

Homework:
Due today: Predicting Products sheet
                   Reactions lab (for those in class Thursday)
Due tomorrow: Mole-Mole Stoich sheet

What did we learn about today?

Stoichiometry 

What is it?

Dictionary Definition: 

1. The calculation of the quantities of chemical elements or compounds involved in chemical reactions.

1. The branch of chemistry dealing with relationships of combining elements, especially quantitatively.

More basic terms...
Stoichiometry is basically the art of finding how much of an element to use in order to cause a chemical reaction, based on the ratios given in a balanced equation. 

Application: Sample #1 (from notes)

Equation: CH4 + 2O2 > 2H2O + CO2Question: How many moles of CH4 are needed to make 13 moles of water?Set Up (it's just like a conversion- so easy!): 13 φ H20 x 1φCH4 
                                                                                          ---------- =  6.5 φ CH4
                                                                                          2 φ H2O 
                                                                
Remember.. molar ratio = φ wanted
                                          -------------
                                           φ given     You get the information from given balanced equation!

Also in class today...
 Mr. Lieberman shot a cannon using a chemical equation- science is cool! I don't have any footage though, sorry. 

NEXT SCRIBE (DRUM ROLL PLEASE) .........
YASMEEN M.

Chemical Reactions Lab

Due Today: Types of reactions worksheet

We started class with going over some homework questions from 'types of reactions' worksheet. Then we started our Chemical Reactions Lab. There were 7 different stations with different instructions. We were suppose to follow the instructions, and write down the observations and chemical formula onto our lab books. Here are the 7 different instructions: (Don't worry if you didn't finish them)

LAB GOAL: To identify each type of chemical reaction for 7 lab stations.
DATA: A table for the observation and chemical formula for each stations.
CONCLUSION:
Claim: Identify each type of reaction that you observed.
Evidence: What observation did you make that back up your claim? (be specific)
Reasoning: What are 5 different types of observation we can make to identify a chemical reaction

One of the reactions that happened in the lab today

Homework: 

1. Predicting Products worksheet (It's on Moodle)
2. Chemical Reactions Lab (due Monday)

DON'T FORGET THAT THERE'S A QUIZ TOMORROW!!

Next scribe....Georgia K

Homework: 

Due Today: Balancing Equations worksheet

Due Tomorrow: Types of Reactions Worksheet

There is a quiz this Friday!

Today we learned about how to identify different kinds of chemical reactions. 

Synthesis Reactions: This is the first type of a chemical reaction. They occur when two substances combine and form a new compound. 

A+B ---> AB

Or to put it in terms of real elements: 

C + O2 ---> CO2

Or, as Mr. Lieberman showed us in class, a balloon filled with hydrogen and an oxygen-driven flame combine to form Hydrogen Peroxide (And an explosion).

2H2 + O2 ---> 2H2O2

                                            

                           

Decomposition Reactions: These occur when one compound separates into its separate elements. 

AB ---> A + B

Or, in elemental terms: 2 H2O ---> 2H2 +O2

Mr. Lieberman showed this to us by combining Sodium Chlorate with an oxygen flame to cause the Sodium Chlorate to become Oxygen and Sodium Chloride.

2NaClO3 ---> 3O2 + 2NaCl  

 

Single Replacement Reactions: These occur when one element replaces another in a compound. 

A metal can replace a metal or a nonmetal can replace a nonmetal.

A(metal) + BC(ionic compound) ---> B + AC

Mr. Lieberman showed us this reaction by showing us an aluminum can placed in Copper Nitrate. The Aluminum from the can goes into forming Aluminum Nitrate, and the Copper sinks to the bottom. The Aluminum switches places with the Copper.  

2Al + 3Cu(NO3)2 ---> 3Cu + 2Al(NO3)3       

Double Replacement: These occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound. 

AB(ionic, aquarius compound) + CD( ionic, aquarius compound) ---> AD +BC

Mr. Lieberman showed us this by pouring Lead Nitrate into Potassium Iodide. The Lead bonds with the Iodine to form Lead Iodide, and the Potassium bonds with the Nitrate to form Potassium Nitrate. The Lead Iodide eventually will sink to the bottom of the test tube because it is a solid and the Potassium nitrate is a powder which will be dissolved in the water.

Pb(NO3)2 + 2KI ---> PbI2 + 2KNO3

Combustion: The last type of chemical reaction, these reactions occur when a hydrocarbon reacts with a hydrogen gas. This is also called burning. 

This will always happen with: CxHy(A hydrocarbon) + O2(Oxygen to burn it with) ---> CO2 + H2O. This will always happen with a hydrocarbon.

The Next Scribe is...... Benya C

Hnrs Chem P1 Lieberman-October 9, 2012

Homework

• due today was the Chemthink on chemical reactions
• chemical reactions worksheet due tomorrow
• chapter 3.4 reading and web assign due the day of the test

We started off class talking about the Nobel prizes being awarded this week. If you want to check it out, go to www.nobelprize.org.  

Balancing Equations

•    Reactants-what goes in to the equation
•    Products-what comes out of the equation
•  Law of Conservation of Mass-what goes in must come out.
•  The equation is unbalanced if when written, the products contain atoms that didn't exist in the reactants or one/some of the atoms in the reactants are lost. This is when we need to balance the equation

Some Examples...

N₂+O₂àNO

Al+CuSO₄àCu+Al₂(SO₄)₃

These are unbalanced because the atoms in the reactants don't equal the atoms in the products.

If we balance them, they are...

N₂+O₂à2NO

2Al+3CuSO₄à3Cu+Al₂(SO₄)₃

_{Notice how the reactants and products now have the same number of each type of atom.} 

_{Here's a picture detailing the balanced equation of} 2H₂+O₂à2H₂O

Synthesis reactions-chemical reaction where two or more substances combine to form a compound. 

Reactant+Reactant-->1 Product

C+O₂àCO₂

Decomposition Reactions-Chemical reaction where a compound is broken to form two or more substances

1 Reactant-->Product+Product

2HgO-->2Hg+O2

We will go over the rest of the notes tomorrow

Mr. Lieberman also did a demonstration involving an exploding paint can today. He had a paint can with a small hole on the side of the can. there was also a hole in the lid. He filled the can with methane from the side hole, and lit it with a lighter from the top. it burned the methane slowly for a short time, then, unexpectedly, the can exploded. The explosion couldn't occur at first because there wasn't enough oxygen in the can (it was unbalanced). When the oxygen filled in (balanced the equation) the can exploded.

Next scribe...Jeremy E.

Post for October 3rd, 2012 by Alex S

HW:
1. Get ready for homework quiz tomorrow
2. Empirical and Molecular Formula WS...Due Tomorrow
3. "Crash of Avogadro Airlines Flight 1023" WS...Due Monday
4. Study For Unit 2 Test Friday...  Review Sheets are available on Moodle
5. Bubble Gum Lab...Due Tomorrow

Due Today:
1. Formula Of A Hydrate Lab
2. Percent Composition WS

        Today we discussed the difference between the empirical and molecular formula of a compound, and how to find them using percent composition. Some definitions of the formulas include:

• Empirical Formula- A formula used to show the ratio of the atoms in a molecule (in lowest terms). Examples include CH4 and CH2O. These formulas can't be simplified.
• Molecular Formula- A formula that is a multiple of a compound's empirical formula but is based on the actual molar mass, rather than atoms. Molecular formula= (Empirical formula)n, where n is an integer. Examples include C2H8 [(CH4)2]. This would reflect the molar mass of the compound.

        Here is an example of finding the two formulas to get you on track, using question 14 from the Empirical and Molecular Formula WS.


14. "An unknown compound was found to have a percent composition as follows: 47.0% potassium, 14.5% carbon, and 38.5% oxygen. What is the empirical formula? If the true molar mass of the compound is 166.22 g/mol, what is the molecular formula?"

1. Assume there is 100 g of the substance. So, you would have 47 grams potassium, 14.5 grams carbon, and 38.5 grams oxygen.
2. Find the amount of moles in each part of the compound:

47 g K x 1 mol/39 g= 1.21 mol K

14.5 g C x 1 mol/12 g= 1.21 mol C

38.5 g O x 1 mol/16g= 2.41 mol O

     3. Divide each amount of moles by the smallest amount of moles in any of the atoms to get your ratio (1.21 mol is the smallest amount of moles in this case).

(1.21 mol K/ 1.21 mol) : (1.21 mol C/ 1.21 mol) : (2.41 mol O/ 1.21 mol)= Roughly 1:1:2

     4.  Write the empirical formula using the above ratio: KCO2. If you ever get a ratio like 1:1.5:1, multiply by an integer to get only whole numbers (ex. the empirical formula for the compound in this problem would be K2C3O2 if it had the misbalanced ratio, because it was multiplied by a factor of 2 to get whole numbers.).

     5. To find the molecular formula, first find the molar mass of the molecule used in the empirical formula: 39+12+(2 x 16)= 83

     6. To find n, divide the true molar mass by the molar mass of your empirical formula.

n= 162.22/83, n= about 2

     7. Put n into your molecular formula and simplify.

(KCO2)2= K2C2O4

The Next Scribe will be: Xavier F

Date: October 2, 2012
HW: % concentration worksheet, formula of a hydrate lab

Today, we learned how to find % concentration of an element in each molecule/compound. To do so the total mass number of each type of element is calculated, then its is divided by the total mass of all elements and multiplied by a hundred.

For example: What is the percentage of each element in an H₂O molecule?                                           
A mole of hydrogen weighs 1g (total 2g since 2 hydrogen atoms are present) and a mole of oxygen weighs 16g , the total is 18g. The percentage of hydrogen 2/18x100= 11.1% and the percentage of oxygen is 16/18x100=88.9%.

We also did a lab: Bubble Gum
Lab goal: The purpose of the lab was to determine the percent sugar present in bubble gum and to write an empirical formula for the bubble gum in the form of  G_xS_y , where G is the fictional symbol for bubble gum (513gram/mole), and a fictional symbol for sugar S (342 grams/mole).

                                                                  
Procedure/data: the mass of the wrapper, bubble gum & wrapper , and chewed bubble gum & wrapper is measured.

Calculations: mass of sugar, mass of the gum before chewing,  mass of gum after chewing, % composition the sugar, and finally the moles of sugar and bubble gum are calculated. The final calculation is equal to the variables in the formula.

Conclusion:

• Claim: what is the empirical formula of the bubble gum?
• Evidence: researchers  have found the ideal formula for the Gum is GS2. How does this compare to your ideal formula.
• Reasoning: If you did not chew the bubble gum fully, how would that effect the empirical formula of your sample.                                          

Next scribe will be Alex S.
                

Remember: this lab is due on Wednesday October 3, 2012.

Also wear mismatched clothes for tomorrow!

No homework for today except to study for the test on Friday!

            Today, we needed to determine how many moles of water are present in the compound per mole of Copper (II) Sulfate.

Lab Goal: To determine the formula of the hydrated.

Procedure: First, a clean crucible or flask must be readied. Then, add a reasonable amount of blue hydrated copper (II) sulfate to the crucible or flask. Due to the shortage of crucibles, many students received a flask. Instead, the flask is heated over a Bunsen burner, evenly applying minimal heat. The substance must be heated until the substance turns white. Brown indicated overheated. Upon completion, allow the flask to cool and wipe out any with a tissue or paper towel.

Data & Conclusion:

Mass of empty crucible	19.44	17
Mass of crucible with Hydrated Salt	21.43	19.12
Mass of crucible with Anhydrous salt	20.62	18.44

 Calculate the mass of the hydrated salt:

Mass of crucible with hydrated-Mass of empty flask = Hydrated salt

Calculate the mass and moles of the water lost.

       Mass of Hydrated Salt – Mass of Anhydrous salt = Water Loss

`           Mass of the water / Grams of H2O

Calculate the mass and moles of anhydrous salt.

       Mass of crucible with anhydrous salt – Mass of empty flask

            Mass of anhydrous salt / mass of CuSO4 in grams

Calculate the ratio between moles of water and moles of anhydrous salt.

       Moles of H2O : Moles of CuSO4

Claim: What is the formula of the hydrated salt?

Evidence: What data did you use to prove your claim?

Reasoning: If all of the water was not driven off, how would this affect your formula for the hydrated salt? Be specific.

Next Scribe: FaBIAN

Signed -Josh-