Required+Labs

=Required Labs= * from 11th chem []
 * // 1. Determination of the formula of a compound (also called law of definite composition)* //**

Setup: You massed a piece of magnesium. Burned it in a crucible and found the mass of the magnesium oxide formed. From mass of oxygen and mass of magnesium you determined mole ratio and empirical formula. Heated to constant mass Data: mass Mg mass crucible, mass crucible and ribbon Calculation: mass à moles to mole ratio 2. **//Determination of the percent water in a hydrate*//** Setup : heat blue copper II sulfate x hydrate in a crucible until all water is driven off. Mass the anhydrous salt.
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Data: mass empty crucible, mass hydrate, mass anydrous Calculation: find mass water lost then convert to moles water. Convert mass anhydrous Copper II sulfate to moles copper II. Find mole ratio of water to copper II sulfate. Should be 1:5 therefore formula is CuSO4. 5H2O

3. **//Determination of molar mass by vapor density//** [|http://web.lemoyne.edu/~giunta/chm152L/vapor.html]

Setup: Erlenmeyer with 2 ml volatile liquid with foil cap w/ hole Data: Mass flask with cap Temp boiling water Room pressure Mass flask with condensed liquid after heating and cooling Calculate weight condensed liquid Volume of flask Calculation Molar mass = __mass RT__ PV

4. **//Determination of molar mass by freezing point depression*//** []

Setup (heat 15g naphthalene in a testtube in a hotwater bath until melts. Cool recording time and temp every 30 sec. Graph. Then add 2g unknown. Hot water bath until melts. Record time and temp as cools every 30sec. Graph data on same graph as first

Data Get D T from difference btwn freezing points of lines on graph. Get mass naphthalene and mass unknown

Calculation Find molality from D T=Kf x //m// x i Find moles unknown from molality using molality- moles solute/kg solvent Find molar mass unknown by mass unknown solute/moles solute

5. **//Determination of molar volume of a gas*//** []

Using magnesium ribbon in a cage, a eudiometer tube and HCl. Data: record mass Mg, volume of gas collected, room temperature and barometric pressure. Find volume at STP and 1 mole using PV/nT = PV/nT

6. **//Standardization of a solution by primary standard//** []


 * Setup ** : this was the first step in the volumetric determination of soda ash when you standardized your HCl. We also did it recently in standardizing NaOH. We do it to make sure are concentration is really what we think it is.
 * Data** volume of acid and base used as well as mass of known acid or base used (potassium acid thalate to standardize NaOH and pure sodium carbonate pellets to standardize HCl
 * Calculation ** MV = MV as long as the reaction is 1:1

7. **//Determination of concentration by acid-base titration, including a weak acid or base//** http://www2.vernier.com/sample_labs/CHEM-A-07-COMP-acid_base_titration.pdf
 * Setup ** used Pasco interface and made a graph of volume NaOH vs pH. We started with 25mL unknown acid and put a pH probe in the beaker with an automatic stirrer and drop counter. We dropped NaOH and started PASCO
 * Data/Caculation ** We used drop counter and pH meter and graphed volume NaOH Vs pH . At the equivalence point find volume of NaOH used. Since you know volume of acid you started with in the beaker and concentration of NaOH MV = MV to find concentration acid (as long as 1:1 ratio of acid to base. In polyrotic lab we used H3PO4 so it was 1:3

8. //**D**//**//etermination of mass and mole relationship in a chemical reaction*//**


 * Setup ** sodium bicarbonate adding HCl dropwise until doesn’t react. Predict amount NaCl formed and indicator changed color so we knew no NaCO3 all reacted since its basic and excess HCl would be acidic

9. //Determination of Ka//
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 * Setup ** used Pasco interface and made a graph of volume NaOH vs pH.
 * Data ** May have collected flow rate and did a time Vs pH graph. Knowing concentration base used, volume base at equivalence pt and amount acid titrated. Since equivalence pt moles acid = moles base can use MV(acid)=MV(base)
 * Calculation ** : Using Henderson Hasselbalch, ½ way to equivalence pt was pH = pKa then solve for Ka then use MV = MV to find concentration acid

10. **//Determination of the rate of reaction and its order*//** http://asd1.schoolwires.com/17422061571320847/lib/17422061571320847/Energy_of_activation_for_Clock_Reaction.pdf
 * Setup ** two solutions one containing iodine the other starch. After varying the concentrations of solutions A and B, reaction time until a blue solution was recorded. Graphs of concentration vs time, ln conc vs time and 1/conc vs time was done
 * Data ** amounts of solutions and dilutions; time
 * Calculation ** calculation of ion concentration and graphs

11. **//Analytical gravimetric determination//**
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 * Setup ** an unknown with chlorine : react with silver nitrate and determine mass of silver chloride produced…watch near light. AgCl will decompose in sunlight
 * Data: ** concentration AgCl; amount AgCl, mass sample initial, mass AgCl produced.
 * Calculation. ** Using percent composition of AgCl, mass of Cl determined. %Cl = mass Cl/sample mass initial

12. **//Determination of enthalpy change associated with a reaction*//** This lab can be found at the following web site: [|http://www.frontiernet.net/~jlkeefer/heat_of_neutralization.doc]

An online lab version: []
 * Setup:** mixing HCl with NaOH. Recording temperature of each reactant and water initially then temperature after mixing. Use a coffee cup calorimeter
 * Data: ** mass, temperature
 * Calculation ** calculate q using q=mC D T then realize q water gained or lost is q reaction gained or lost which is Hrxn (C is calorimeter constant)

13. **//Colorimetric or spectrophotometric analysis//** [|http://www2.truman.edu/~blamp/chem222/manual/pdf/ironspec.pdf]
 * Setup: ** Colorimetric iron. Using spectrophotometer. Know what a calibration curve is for, that you are graphing concentration of solution VS absorbance, know Beer’s law, know how a spectrophotometer works,

14. **//Separation by chromatography//**
We did cations of Fe, Ni and Cu. You reacted with different compounds like ammonia to bring out the colors []
 * Setup: ** Ink and oR unbknown cation sokution placed on chromatography strips as well as on a circular filter paper, water not touching dot. Water climbs paper and carries ink. Intermolecular attractions and different mass of particles causes separation.

15. **//Separation and qualitative analysis of cations and anions//**
Cations and anions present are determined through solubility rules and colors of precipitates. Based on the precipitates formed, your unknown ions can be identified. Have a good idea what compounds with precipitate what ions as well as the precipitate color. See the following web sites for a sample lab [|http://web.umr.edu/~gbert/qual/qual.html]

16. **//Synthesis of coordination compound and its chemical analysis//** We didn’t discuss coordination compounds this year. A brief overview in 24.1-24.3. You might want to glance at it in case. A sample lab is the following web site [|http://www.macalester.edu/~kuwata/Classes/2004-05/chem%20111/111l%20experiment%206%20-%20co%20synthesis.pdf]

[|**//__17. Preparation and properties of buffer solutions__//**] []
 * Setup: ** basically, this lab involves making a buffer solution. Key ideas, adding a salt of the conjugate base of the weak acid used. The moles of conjugate base should be close to the moles of weak acid. Different amounts of 1M HCl is added as well as different amounts of 1 M NaOH to see the effect on pH. The buffer capacity is determined. (the max amount of strong acid or base that can be added to the buffer until the buffer can no longer neutralize it. You will see a large jump in pH at this point.

18. **// Determination of electrochemical series //** * This lab was done last year as the Activity series lab. There is one online like the one we did if you can’t find it. []

Basically, you take different metals and react them with different solutions and determine order of reactivity. Remember, all a single replacement reaction is a redox reaction. You can tie this directly to the reduction potential sheet in chapter 20

19. **// Measurements using electrochemical cells and electroplating( //**** lecture ** )
 * Setup ** actually making an electrochemical cell and seeing a metal being electroplated. Based on the masses of the electrodes before and after the experiment, one can determine the cell voltage.

We did sample problems in section 20.9 in textbook __[]__

20. **//Synthesis, purification and analysis of an organic compound//** This lab is the making of aspirin and testing its purity. It can be found online at

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[|http://db.mctc.mnscu.edu/chemistry/resources/Introlabmanual/Exp7.pdf]

21.**//Determination of concentration by oxidation reduction titration//** [] []

Online chem. Labs [] 22. **//Determination of appropriate indicators for a titration

23. Determination Ksp//**
 * // Using spectrophotometer. We measured standard concentration of yellow chromate ion solution and made a calibration curve, then mixed silver nitrate and potassium chromate to get red silver chromate. We took the solution that had maintained equilibrium after centrifuging and put solution in spectrophotometer to find concententration of chromate. We knew concentration Ag was twice that of chromate. Found Ksp by Ksp=[Ag+]2[CrO42-] //**
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 * // These labs coordinated with AP questions. I attached a copy //**


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