A certain person had a brain that weighed 1.10 kg and contained 3.51 x 10^10 cells. Assuming that each cell was completely filled with water (density = 1.00 g/mL) calculate the length of one side of such a cell if it were a cube.

If the surface were spread out into a thin layer that was a single cell thick what would be the surface area in square meters?

Determine the theoretical yield and the percent yield if 21.8 g of K2CO3 is produced from reacting 27.9 g KO2 with 29.0 L of CO2 (at STP).   The molar mass of KO2 = 71.10 g/mol and K2CO3 = 138.21 g/mol.

Consider the reaction that converts pyruvic acid (CH3COCOOH) into gaseous acetaldehyde (CH3CHO) and gaseous CO2, which is catalyzed in aqueous solution by the enzyme pyruvate decarboxylase. Assume ideal gas behavior for CO2.

Calculate ?rG (298 K) for this reaction at 160 bar.

A 50 mm internal diameter horizontal steel pipe carrying steam is covered by a 50 mm thick layer of a ceramic insulation material and is tightly wrapped with a 0.5 mm thick layer of clean aluminum foil. The wall thickness of the steel pipe is 3.9 mm. The entire pipe is surrounded by air at 20°C. The emissivity of the aluminum foil can be taken as 0.05. Determine the steady-state temperature of the outside surface of the aluminum foil if the temperature of the inner surface of the steel tube is 122°C. The thermal conductivity values are: for steel: 45 W/(m.K), for the insulation: 0.07 W/(m.K); for aluminum foil: 167 W/(m.K). {Hint: you have to account for both convective and radiation heat loss to the surroundings.}

These are post lab questions regarding paper chromatography. Some background. The solvent used was a mix of HCl and acetone. We spotted the paper with 4 ions including Co(II), Cu(II), Fe(III), and Ni(II). After the solvent nearly reached the top, the paper was removed and measurements were made. Paper was dried and sprayed with ammonia. Changes observed and the paper was dried again and sprayed with sodium sulfide. Pleas help!

a)You used a pencil to mark the chromatography paper since the carbon in the pencil lead does not dissolve in the solute. Why does carbon not dissolve? What type of pen(ink) will also not produce a chromatogram when watert is used as the solvent? Explain using principles based on the polarity of particles.

b)You are to minimize hand contact with the paper since amino acids, oils, etc. on your skin will form a smudge on the cellulose paper. Why will using corroded tweezers also cause a smudge when sodium sulfide is sprayed on the paper?

c) What type of complexes appear when the spots are sprayed with Ammonia and why do new colors appear?

d) Same question as 'c' but being sprayed with sodium sulfide

Equilibrium Constant

1) The Kc value for the following equilibrium at 500 degrees Celcius is 49.

H2(g) + I2(g) = 2HI(g)

If 1.00 moles of H2 and 2.00 moles of I2 are introduces into a 3.00 L flask at 500 degrees celcius, how many moles of HI are present at equilibrium?

2) What would happen to the values you calculated for Kc in the experiment if the Beer's Law constant (k) value you used was low (e.g. you used 6000 M^-1 when the actual constant had a value of 10,000 M^-1) ? Explain your answer.

3) 1/2N2(g) + O2(g) = NO2(g) Kc = 1.04 x 10^-9

N2(g) + 2O2(g) = N2O4(g) Kc = 7.42 x 10^-18

Calculate Kc for each of the following.

(a) 2NO2(g) = N2(g) +2O2(g)

(b) N2(g) + 2O2(g) = N2O2(g)

(c) 2NO2(g) = N2O4(g)

2. (10 pts) Determine , and when 100.0 g of hydrogen reacts with sufficient amount of nitrogen to form ammonia at standard thermodynamic conditions. Determine Δ H, ΔU , ΔA , ΔG ,ΔS , q and w. The enthalpies of formation and entropies are: ΔHf = { H2= 0, N2 =0, NH3 =-46.1} Sْ = { H2 =130.68 , N2 = 191.61 , NH3 = 192.45 }

Which species has a normal boiling point closest to the normal boiling point of argon, Ar? (A) H2 (B) N2 (C) F2 (D) Cl and why

When 1.95 grams of Co(NO3)2 is dissolved in 0.750 L of 0.220 M KOH, what are the [Co 2+], [Co(OH)4 2-], and [OH-] if Kf of Co(OH)4 2- = 5.00x10^9?

Which of the following descriptions and/or equations best represents the enthalpy change of a system? There may be more than one correct answer.

A. The heat absorbed or released during a phase change or chemical reaction at constant pressure

B. The work done on or by a phase change or chemical reaction at constant pressure

C. deltaH = deltaE + PdeltaV

D. deltaE = q + w

E. H= E + PV

F. The heat sborbed or released during a phase change or chemical reaction at constant volume

G. The amount of energy required to raise the temperature of 1 mole of a substance by 1 degree C at constant pressure

H. The sum of the internal energy and the pressure-volume product of a system

For each of the following reactions provide a balanced chemical equation suppose exactly 5.00g of each reactant is taken. Determine which reactant is limiting and calculate what mass of each product is expected . (Assume that the liminting reactant is completely consumed).

identify the oxidizing agent in the reaction: Fe(s)+Cu(No3)2(aq)->Fe(NO3)2(aq)+Cu(s)

Determine the pH at the equivalence point for the titration of 40.0 mL of 0.1 M HNO2 by 0.200 M KOH. (The pK_a of nitrous acid is 3.36.)

Section A

1. Explain what happens to the pH paper in each of the following cases, and whether the substance is acid or base.

(a) Dry pH paper, household ammonia

(b) Moist pH paper, household ammonia

(c) Bleach

(d) Ammonium carbonate

2. Why are most cleaning agents and detergents basic?

Section B

3. What happens when you mix baking soda with vinegar? Describe your observations and write a balanced chemical equation to explain them.

4. What do you think would happen if you mixed the baking soda with concentrated sulfuric acid instead? What differences would you expect and why? Write and explain a balanced chemical equation for this reaction.

Section C

5. Do you see a trend in the periodic table that is related to the trend in the conductivity measurements? Explain why this trend occurs.

Section D

8. Explain your observations for Na vs. Ca in water. Write properly balanced chemical equations for the reactions, and explain the differences in your observations between the two elements based on their locations on the periodic table.

Section E

9. Explain how your observations relate to the positions of each element in the periodic table.

Section F

10. Explain how the reactivity with acid relate to the location of each substance on the periodic table.

Thank you so much!!!! :)

compare the rreducing capability of Lithium,Almunium hydride to those of sodium borohydride??