Mothballs are composed primarily of the hydrocarbon naphthalene (C10H8). When 1.025 g of naphthalene is burned in a bomb calorimeter, the temperature rises from 24.25 ?C to 32.33 ?C.

Find ?Erxn for the combustion of naphthalene. The heat capacity of the calorimeter, determined in a separate experiment, is 5.11kJ/?C.

Express the change in energy in kilojoules per mole to three significant figures.

Pure copper may be produced by the reaction of copper(I) sulfide with oxygen gas as follows:

Cu₂S(s) + O₂(g) → 2Cu(s) + SO₂(g)

If 0.490 kg of copper(I) sulfide reacts with excess oxygen, what mass of copper metal may be produced?

A 35.00-mL solution of 0.2500 M HF is titrated with a standardized 0.1120 M solution of NaOH at 25 C

1) the pH at 0.50 mL before the equivalence point
2) the pH at the equivalence point
3) the pH at 0.50 ml after the equivalence point.

Assume that all 4.0 mL of methyl salicylate was placed in the beaker and reacted, that most of the NaOH solution is water, and that the total water used is 56 mL. The density of methyl salicylate is 1.18 g/mL and the density of water is 1.00 g/mL. Pay close attention to units and dimensional analysis when completing this problem.

Predict under what temperatures (all temperatures, low temperatures, or high temperatures), if any, the reactions will be spontaneous or nonspontaneous.

Part A) N2(g)+O2(g)→2NO(g) ΔH∘rxn=+182.6kJ

Part B) 2N2(g)+O2(g)→2N2O(g) ΔH∘rxn=+163.2kJ

Part C) 4NH3(g)+5O2(g)→4NO(g)+6H2O(g) ΔH∘rxn=−906kJ

A 5.65 −g sample of a weak acid with Ka=1.3×10−4 was combined with 5.20 mLof 6.10 M NaOH and the resulting solution was diluted to 750 mL. The measured pH of the solution was 4.20.

What is the molar mass of the weak acid?

In a waste-water treatment plant a 1.00x10³ L tank with 3.00x10^-2 M Na₂CO₃(aq) is mixed with a 2.00x10³ L tank with of 6.00x10^-3 M Na₂CO₃(aq). Assume sodium carbonate behaves as a strong electrolyte.

a) How many moles of sodium ions are in the product?

b) What is the concentration (in M) of sodium ions in the product?

The acid dissociation constant of the 1,10-phenanthrolium ion (phen) was meeasured at different temperatures using spectroscopic methods.

The values of pKa measured at 298K and 308K were 4.812 and 4.731, respectively.

Part A: Calculate  ΔrGo at 298K. Express your answer in kJ/mol to three significant figures.

Part B: Calculate  ΔrGo at 308K. Express your answer in kJ/mol to three significant figures.​

Part C: Calculate  ΔrHo. Express your answer in kJ/mol to three significant figures.​

Part D: Calculate  ΔrSo. Express your answer in J/(K.mol) to three significant figures.​

Part E: Calculate the pKa of the acid at 359K. Express your answer to three significant figures​

A student finds that a mixture of acetone and water at 740 mmHg boils at 68 Celcius. Pure acetone has a vapor pressure of 1200 mmHg and water has a vapor pressure of 237 mmHg at the given temperature.

a.) What are the mole fractions of each component in the mixture?

b.) If there are 0.500 moles in the solution, what is the composition by mass, of the mixture?

give us your version of Emil Fischer's proof of the structure of glucose. You do not need to flesh out Fischer's proof to reveal the structures of all the D-aldopentoses and D-aldohexoses, but you do have to show us structures for the four sugars (three D, one L) that come directly from the Fischer proof, the determination of the structure of D-Ribose, and mechanisms for all reactions you (and Emil Fischer) use(d).

For the reaction SO₂(g) + NO₂(g) == NO(g) + SO₃(g), Kc = 85.0 at 460

Questions

A.      Use your results to determine if the forward reaction in the potassium chromate/HCl reaction endothermic or exothermic. Explain your answer, using Table 1 to help construct your thoughts.

B.      Write the equation for the equilibrium constant (K) of the reaction studied in this exercise.

2K2Cr4 + 2HCl ------> Cr2o7 + H2O + 2KCl

Use the information below to answer Questions C, D, and E:

The equilibrium constant (K) of the reaction below is K = 6.0 x 10^-2, with initial concentrations as follows: [H₂] = 1.0 x 10^-2 M, [N₂] = 4.0 M, and [NH₃] = 1.0 x 10^-4M.

N2 + 3H2 ------> 2NH3

If the concentration of the reactant H₂ was increased from 1.0 x 10^-2 M to 2.5 x 10^-1M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.

If the concentration of the reactant H₂ was decreased from 1.0 x 10^-2 M to 2.7 x 10^-4M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.

If the concentration of the product NH₃ was decreased from 1.0 x 10^-4 M to 5.6 x 10^-3M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.

Exercise 2.58. Part A: Determine the number of Kr atoms in a 5.55 −mg sample of krypton.

Part B:Determine the molar mass, M, of an element if the mass of a 2.80×1022−atom sample of the element is 2.09 g.

Part C: Determine the identity of an element if the mass of a 2.80×1022−atom sample of the element is 2.09 g. (Answer choices: titanium. potassium, scandium, calcium.)

Exercise 2.56. Without doing detailed calculations, indicate which of the following quantities contains the greatest number of atoms: 6.022×1023Ni atoms, 25.0 g nitrogen, 52.0 g Cr, 10.0cm3 Fe (d=7.86g/cm3). (answer choices: Ni, Nitrogen, Cr, Fe)

Excercise 2.62. A particular lead–cadmium alloy is 8.0% cadmium by mass. What mass of this alloy, in grams, must you weigh out to obtain a sample containing 6.30×10²³ Cdatoms? Express your answer using two significant figures.

Exercise 3.6 Determine the mass, in grams, of,

Part A 7.32 mol N2O4

Part B 3.22×10²⁴ O2 molecules

Part C 18.8 mol CuSO4⋅5H2O

Part D 4.14×10²⁴ molecules of C2H4(OH)2

Excercise 3.11

Part A moles of N2O4 in a 145 −g sample

Part B N atoms in 43.5 g of Mg(NO3)2

Part C N atoms in a sample of C7H5(NO2)3 that has the same number of O atoms as 12.4 g C6H12O6

thank you in advance ^^

Calculate the free-energy change for ammonia synthesis at 25 ? C(298 K) given the following sets of partial pressures:

a.1.0 atm N2, 3.0 atm H2, 0.020 atm NH3

b. 0.010 atm N2, 0.030 atm H2, 2.0 atm NH3

1. The molecular weight of anhydrous calcium chloride is 110.99 grams/mol. How many grams do you need for 750 ml of 250uM calcium chloride?

2. Ethanol is supplied in a 90% solution. You need 275 mL of 75% Ethanol for your experiment. How would you make this solution?

3.You have 12 mL of cells you need to treat with Hydrogen Peroxide (H₂O₂), such that the final concentration of H₂O₂ is 50 uM. How much of a 30 mM stock solution of H₂O₂ would you add to your cells?

4. You need to prepare a stock solution of medium for your culture cells, which usually includes liquid salt solution and bovine serum. Your liquid salt solution is supplied in a 50X concentration, and you need to dilute it to 1X for use. You also need to add 75% fetal bovine serum for a final concentration of 15%. How would you make up 0.80 liters of this culture media using water as your solvent?

5. You need to treat cells with arsenite such that it has a final concentration of 25 uM once it has been added to the cells. You need to treat 10mL of cells, and you don't want your treatment volume to be more than 7 uL per 1mL of cells. What concentration should you make your stock solution?