A molecular compound contains 92.3% carbon and 7.7% hydrogen by mass. What is the empirical formula of this compound? If 0.592 mol of the compound weighs 30.78g, what is its molecular formula?

1) A 10.00 ml sample of an aqueous solution of calcium hydroxide is neutralized by 20.00 ml of 0.02000 M NHO₃(aq). What is the molarity of the calcium hydroxide solution? Enter only a numerical value, do not enter units.

2) Suppose you titrate 80.0 mL of 2.00 M NaOH with 20.0 mL of 4.00 M HCl. What is the final concentration of OH^- ions. Enter only a numerical value, do not enter units.

3) Suppose a solution is prepared by dissolving 15.0 g NaOH in 0.150 L of 0.250 M nitric acid. What is the final concentration of OH^- ions in the solution after the reaction has gone to completion. Assume that there is no volume change when adding the grams of NaOH. Enter only a numerical value, do not enter units.

4) A monoprotic acid is an acid that donates a single proton to the solution. Suppose you have 0.140 g of a monoprotic acid dissolved in 35.0 mL of water. This solution is then neutralized with 14.5 mL of 0.110 M NaOH. What is the molar mass of the acid? Express your answer in g/mol. Enter only a numerical value, do not enter units.

5) Which combination of name and formula is NOT correct.

                   a) Barium hydroxide, Ba(OH)₂(aq)

b) Potassium peroxide, K₂O₂(s)

                   c) Phosphoric acid, H₃PO₄(aq)

                   d) Iodic acid, HI(aq)

                   e) Perchloric acid, HClO₄(aq)

2. At 500 °C, cyclopropane (C3H6) rearranges to propene (CH3CH=CH2):   C3H6 (g) ------> CH3CH=CH2 (g)

The reaction is first order and the rate constant is 6.7 x 10-4 s-1. (a) What is the rate law for the reaction, and; (b) if the initial concentration of C3H6 is 0.100 M, what is the concentration of cyclopropane of after 20 min?

3. Butadiene (C4H6) reacts with itself at 250 °C to form a dimer with the formula C8H12.

2 C4H6 (g) ----> C₈H₁₂ (l)

The reaction is second order in C4H6. (a) What is the rate law for the reaction, and; (b) if the rate constant is 4.0 x 10-2 M-1.s-1, and the initial concentration of C₄H₆ is 0.200 M, how long will it take for the concentration of C4H6 to reach 0.04 M?

4.    a) In Q. 2 above what is the half life for the reaction and what is concentration of C₃H₆ after 3 half-lives

   b) In Q. 3 above how long are the first and second half-lives?

I did an organic chemistry lab where I purified a sample of crude biphenyl. The following questions are in regard to the lab.

a. More polar solvents move molecules more rapidly than less polar solvents. If you used a 1:1 hexanes: methanol instead of the 4:1 hexanes:ethyl acetate, would the products elute fater or slower? is the mixture of 1:1 hexanes:methanol a good choice as an eluent with biphenyl?

b. Why do impure compounds have lower melting points than the pure samples? Explan in molecular terms using biphenyl as an example. (we removed methyl orange from biphenyl)

c. Naphthalene has a melting point of 80.3 degrees Celcius. Is that higher or lower than the melting point of biphenyl? Explain the answer in molecular terms (biphenyl has 2 rings connected with a bond and Napthalene is 2 fused rings)

What shape heating and cooling curves suppose to have?

The rate of reduction of [Co(NH3)5(OH2)]3 by Cr(II) is seven orders of magnitude slower than reduction of its conjugate base, [Co(NH3)5(OH)]2, by Cr(II). For the corresponding reductions with [Ru(NH3)6]2, the two differ by less than a factor of 10. What do these observations suggest about their mechanisms?

Derive a balanced equation for the reaction occurring in the cell:
Fe(s)|Fe²⁺(aq)||Fe³⁺(aq),Fe²⁺(aq)|Pt(s)

a.) If E?cell = 1.21 V, calculate ?G? for the reaction.

b.) If E?cell=1.21V, calculate the equilibrium constant for the reaction.

c.) Use the Nernst equation to determine the potential for the cell:
Fe(s)|Fe²⁺(aq,1.0�10^-3M)||Fe³⁺(aq,1.0�10^-3M),Fe²⁺(aq,0.10M)|Pt(s)

You need to make a benzoic acid-based buffer that has a ph of 5.10. The volume should be 500ml. What masses of the acid and its conjugate base should you use? (Hint: you should not go over 1M in concentration for either acid or conjugate base) Show all Work.

Part B. The pH of the above buffer solution should not go above 5.15. If 10ml of 0.1 M NaOH is added to the buffer, will the pH go past the maximum value?

Show using the C4v point group character table the orthogonality of any two irreducible representations.

Using the same point group demonstrate the property of the character table that two irreducible representations can be used to deduce the characters for another (ex combinations of the irreducible representations for px and py can be used to determine the characters for the irreducible representation of dxy)

Calculate the activity of 30 g of radium-226 in Bq and mCi. ( The half-life of radium-226 is 1600yeras.) Ci ( = 3.7 times10^10Bq)

For a weak acid, HA,

1) write the ionization reactionin water

2) write the expressio of its acid ionation constant, Ka

3)If Ka is 1.0 x 10^-6, calculate the pH of a 0.200-M Ha solution

4)What is the pH of a buffer solution with 0.35 M HA and 0.40 M A-?

1) The Ka of a monoprotic weak acid is 2.47

URGENT!! Solid carbon can react with gaseous water to form carbon monoxide gas and hydrogen gas. The equilibrium constant for the reaction at 700.0 K is Kp=1.60×10−3. Part A If a 1.55-L reaction vessel initially contains 121 mbar of water at 700.0 K in contact with excess solid carbon, find the percent by mass of hydrogen gas of the gaseous reaction mixture at equilibrium.

I've tried 4 times, I keep getting it wrong. Please show me how to do it! It is due very soon.

Three major spectroscopic methods for elemental analysis atoms are Atomic Absorption Spectroscopy, Atomic Emission Spectroscopy, and Atomic Mass Spectroscopy. Briefly describe the physics behind each of the three methods.