1. Calcium oxalate monohydrate, CaC2O4•H2O, is stable up to ~100˚C, but will release the incorporated water molecule when heated to 300˚C, according to the following reaction:

CaC2O4•H2O(s) → CaC2O4(s) + H2O(g)

If a 4.1754 g sample of calcium oxalate monohydrate is heated to 300˚C, what should be the mass (g) of the resulting calcium oxalate?

2. An unknown sample of ore with a mass of 506.1 g is allowed to react with excess magnesium and ammonia, NH3, in order to analyze for phosphate, PO43-, according to the following precipitation reaction:

2PO43-(aq) + 2Mg2+(aq) + 2NH3(aq) + 2H2O(l) → Mg2(P2O7)(s) + 2NH3(aq) + 2OH-(aq) + H2O(l)

After the precipitated Mg2(P2O7) is carefully rinsed and dried, the mass is determined to be 0.09870 mg.
Assuming all phosphorous originally present in the ore was in the form of phosphate, what was the original mass (μg) of phosphorous in the ore sample?

3. An unknown organic compound was produced by students in the O-chem lab. According to their records, this compound should only contain carbon and hydrogen atoms. A combustion analysis is performed on the sample.

When 0.1727 g of the sample is burned in the presence of excess oxygen, the magnesium perchlorate cartridge increases 0.24889 g and the ascarite cartridge increases 0.53094 g.

What is the percent C (w/w) in the sample?

4. What is the percent H (w/w) in the sample?

5. What is the empirical formula for the unknown compound?

Consider the reaction

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

at 63 ∘C , where [Fe2+]= 2.90 M and [Mg2+]= 0.210 M .

Part A

What is the value for the reaction quotient, Q, for the cell?

Express your answer numerically.

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Part B

What is the value for the temperature, T, in kelvins?

Express your answer to three significant figures and include the appropriate units.

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Part C

What is the value for n?

Express your answer as an integer and include the appropriate units (i.e. enter mol for moles).

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Part D

Calculate the standard cell potential for

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

Express your answer to three significant figures and include the appropriate units.

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Part E

What is the cell potential for the reaction

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

at 63 ∘C when [Fe2+]= 2.90 M and [Mg2+]= 0.210 M .

Ozone gas, O3 decomposes into O2 in presence of NO and gaseous O atoms The following data was obtained Determine the experimental rate law for the reaction given the following data and the value for the rate constant

O 3= 2.3 x 10^-4 atm NO = 1.6 x 10^-4 O = 1.5 x 10^-4 rate1 = 2.6 x 10-3

O3 = 2.3 x 10^-4 NO = .8 x 10^-4 O = 1.5 x 10^-6 rate 2 = 1.3 x 10^-3

O 3 = 4.6 x a0^-4 NO = 1.6 x 10^-4 O = 1.5 x 10^-6 rate 3 = 5.2 x 10^-3

O3 = 4.6 x 10^-4 NO = 1.6 x 10^-4 O = 3.0 x 10^-6 rate 4 = 5.2 x 10^-3

What is the predominant intermolecular force in the liquid state of each of these compounds: ammonia (NH3), carbon tetrachloride (CCl4), and hydrogen sulfide (H2S)? Drag the appropriate items to their respective bins.

Consider a system consisting of a cylinder with a movable piston containing 10⁶ gas molecules at 298 K at a volume of 1 L. Consider the following descriptions of this system:

A. Initial system as described above.

B. Starting from the initial system, the volume of the container is changed to 2 L and the temperature to 395 K.

C. Starting from the initial system, a combination reaction occurs at constant volume and temperature.

D. Starting from the initial system, the gas reacts completely to produce 10⁷ gas molecules at 395 K in a volume of 2 L.

Arrange the descriptions in order of increasing number of microstates in the resulting system. Explain the rationale for your ranking.

Is this ranking the same order as if you ranked the systems according to increasing entropy?  

What are the three basic types of solids and the composite units of each? What types of forces hold each type of solid together?

Applying the phase rule. Consider the phase diagram for a one-component system.

(a) What is the variance and number of phases at (T1, p1)?

(b) What is the variance and number of phases at (T2, p2)?

(c) What is the variance and number of phases at (T3, p3)?

(d) Which is the triple point?

What volume of each of the following acids will react completely with 50.32 mL of 0.120 M NaOH?

(a)    0.130 M HCl
mL

(b)    0.180 M H₂SO₃ (two acidic hydrogens)
mL

(c)    0.210 M H₃PO₄ (three acidic hydrogens)
mL

(d)    0.135 M HNO₃
mL

(e)    0.255 M HC₂H₃O₂ (one acidic hydrogen)
mL

(f)    0.320 M H₂SO₄ (two acidic hydrogens)
mL

lab report for separation and purification of benzoic acid, benzoin, 1,4-dibromobenzene

1. There is nothing like the smell of BBQ in the summertime. Many people use propane gas Barbeques to cook the perfect steak. Here is the reaction that is occurring while the steak sizzles on the grill:

C₃­H₈(g)   + O₂(g) --> CO₂(g) +   H₂O (g)

The balanced reaction has a DH^o_rxn = -2217 kJ. If a steak must absorb 7.2x10^-4 kJ to reach a perfect medium rare, and if only 15% of the heat produced by the barbeque is actually absorbed by the steak, what mass of H₂O is emitted into the atmosphere when this steak is cooked? (Hint: don’t forget to balance the reaction)

2. A student performed this lab with a marshmallow. He used 50.0 g of water and recorded a temperature of 21°C before heating and 30°C after heating. The marshmallow and fork weighed 21.5 g before heating and 21.1 g after heating. What was the total energy (in J) of the marshmallow? What was the energy per gram of the marshmallow?

The commercial concentrated hydrochloric acid is rated at 38 w/w%. The density of the solution is d = 1.18g.mL. Calculate the molarity of HCl (cHCl), molality of HCl (cR,HCl), and the mole fraction of HCl (xHCl).

If the observed rate law for a reaction is: rate = k(NO)(O₃), the reaction is

A. first-order overall

B. first-order in O₃

C. third-order overall

D. second-order in NO

(a) At what temperature do the Fahrenheit and Celsius scales have the same numerical value? (b) The Fahrenheit and Kelvin scales? (c) Describe the basis of each of these three temperature scales. The two cryogenic liquids I use in the lab are liquid nitrogen and liquid helium. What are the boiling points of those two liquids (e) in Fahrenheit? (f) in Kelvins?

Many years ago, I was obliged to polish to a mirror finish the leather shoes and belt of a certain sergeant to a mirror finish. The only way of achieving the desired result was to use copious quantities of spit, a trick which was taught to me by various people who had spent time in the army. My question is ... why does spit enhance the shine of shoe polish? And perhaps a related question ... modern shoes don't seem to require polishing. What surface finish is applied in the manufacturing process which gives an everlasting shine?

calculate the concentration of nickel (II) ion in the solution after the addition of 25.0 mL of 0.200 M NaCN to 60.0 mL of 0.0100 M Ni(NO3)2 (Kf is 2.0x10^31 for [Ni(CN)4]^2-)