Some commercial drain cleaners contain a mixture of sodium hydroxide and aluminum powder. When the mixture is poured down a clogged drain, the following reaction occurs:

2NaOH(aq) + 2Al(s) + 6H₂O(l) → 2NaAl(OH)₄(aq) + 3H₂(g)

The heat generated in this reaction helps melt away obstructions such as grease, and the hydrogen gas released stirs up the solids clogging the drain. Calculate the volume of H₂ formed at 23°C and 1.00 atm if 3.12 g of Al are treated with an excess of NaOH.

The metabolic oxidation of glucose, C₆H₁₂O₆, in our bodies produces CO₂, which is expelled from our lungs as a gas:

C₆H₁₂O₆(aq) + 6O₂(g) → 6CO₂(g) + 6H₂O(l)

Calculate the volume of CO₂ produced at body temperature (37°C) and 0.970 atm when 24.5 g of glucose is consumed in this reaction.

Calculate the volume of oxygen you would need, at 1.00 atm and 298 K, to completely oxidize 50.0 g of glucose.

Ammonia (NH₃) boils at -33.4 ^oC. It has an enthalpy of vaporization of 23.35 kJ/mol. The liquid has a specific heat of 80.8 J/mol ^oC, and the gas has a specific heat of 35.06 J/mol ⁰C.

A 34.06 gram sample of ammonia was heated, at 1 atmosphere pressure, from -40 ^oC to room temperature (25 ^oC). How many kJ of thermal energy did the sample absorb from the surroundings in this process?

I got 101263.8J (101.3kJ) and it is NOT correct, please help with the correct answer.

you want to purify 10g of a compound A that has been contaminated with 0.20g of compound B. solubilities in water of the two compounds are given.

compound A - solubility at 20°c= 0.029g/mol, solubility at 100°c= 0.680g/mol

compound B - solubility at 20°c = 0.22, solubility at 100°c = 6.67

a) what volume of boiling water is needed to dissolve 10g of compound A?

b) How much of compound A will remain after cooling to 20°c?

c) what is the maximum amount of compound A that can be recovered in the first crop of this recrystallization?

d) will any compound B crystals form ( will compound B be pure)? show work to explain answer.

make an energy level diagram (electronic transitions) of compound Fluorescein

Using a 0.25 M phosphate buffer with a pH of 7.6, you add 0.75 mL of 0.45 M NaOH to 59 mL of the buffer. What is the new pH of the solution?

The generic metal A forms an insoluble salt AB(s) and a complex AC5(aq). The equilibrium concentrations in a solution of AC5 were found to be [A] = 0.100 M, [C] = 0.0340 M, and [AC5] = 0.100 M. Determine the formation constant, Kf, of AC5. The solubility of AB(s) in a 1.000-M solution of C(aq) is found to be 0.163 M. What is the Ksp of AB?

1.What are the key operating features of the following types of mass spec instruments and what are the advantages and benefits if any associated with each type. (Include quadrupole, triple quadrupole mass spec, ion trap and time of flight) 2. Briefly describe what is Maldi

An unknown mass of each of the following substances, initially at 21.0 ∘C, absorbs 1930 J of heat. The final temperature is recorded as indicated. Find the mass of each substance.

1) Pyrex glass (Tf= 55.7 ∘C)

2) sand (Tf= 62.3 ∘C)

3) ethanol (Tf= 44.4 ∘C)

4) water (Tf= 32.4 ∘C)

Choose all the true statements.

-Liquid water has a lower entropy than liquid benzene at 25°C because of hydrogen bonding in water.

-Entropy is the main driving force in the formation of the DNA double helix.

-All elements in their standard states have an entropy of zero at 25°C.

-Reactions that involve only gases always have a positive change in entropy

-Evaporating a liquid has always a positive change in entropy freezing water is possible only if the entropy of the surroundings increases

-It is impossible to freeze ethanol because the change in entropy of the system is negative.

-Ice at 0°C has a higher entropy than liquid water at 0°C because the density of ice is lower than the density of water.

-Binding a substrate to an enzyme always lowers the entropy because the substrate loses translational and rotational degrees of freedom.

Five moles of TiCl4 are combined with two moles of Ti.

a) How many moles of TiCl3 are produced according to the following reaction?

3TiCl4 + Ti = 4TiCl3

I know the answer for A is 6.7 mols TiCl3.

I know 2 mols of Ti (4 mol TiCl3 / 1 mol Ti) = 8 mol and 5 mols TiCl4 (4 mols TiCl3 / 3 mols TiCl4) = 6.7 mols TiCl3

What I don't understand is where the 5 is coming from. Wouldn't the balanced equation use 6 and not 5?

This is my main question and I would appreciate any detailed replies to help me understand. Thank you.

: A suspension of colloids at room temperature (25°C) contains CaS0₄ in (a) 3 mM and (b) 30 mM concentration. Find the Debye length (in nm) for both the cases. Use relevant data given in lecture 12-13. (c) Why do you suppose the Debye length changes with change in salt concentration? Provide reasoning from colloidal science to support your answer. (d) If NaCI was used instead of CaS0₄, how would the Debye length values change for cases (a) and (b)? (No calculation necessary for part (d))

What is the systematic name of [Os(NH3)2(en)2]Cl3, [Co(NH3)3(en)Cl]NO3, and (NH4)2[Fe(EDTA)]?

1). Two 20.0 mL samples, one 0.200 MKOH and the other 0.200 M CH3NH2, were titrated with 0.100 MHI. Answer each of the following questions regarding these two titrations.

a). What is the volume of added acid at the equivalence point for KOH?

b). What is the volume of added acid at the equivalence point for CH3NH2?

c). Predict whether the pH at the equivalence point for each titration will be acidic, basic, or neutral.

d). Predict which titration curve will have the lowest initial pH.

2). Potassium hydroxide is used to precipitate each of the cations from their respective solution. Determine the minimum concentration of KOH required for precipitation to begin in each case.

a). 1.2×10⁻² M CaCl2

3). Use the Henderson–Hasselbalch equation to calculate the pH of each solution:

a). a solution that contains 1.31% C2H5NH2 by mass and 1.20% C2H5NH3Br by mass

b). a solution that is 11.5 g of HC2H3O2 and 11.5 g of NaC2H3O2 in 150.0 mL of solution

The following rate data was collected for a reaction X + Y -> Products

     Exp.            [X]                         [Y]                Rate of formation of a product

     1                0.23 M                 0.17 M                    0.33 M/h

    2                0.46 M                 0.17 M                    0.66 M/h

    3               0.23 M                0.51 M                    0.99 M/h

a. Determine the orders with respect to the two reactants and write the rate law for the reaction

b. Calculate the value of the rate constant and include the units of the rate constant

16. Does the reaction Cu²⁺ + Mg (s) →    Cu (s) + Mg²⁺ occur spontaneously in aqueous solution?

            A.     yes                      B.    no

17. Does the reaction 2 Al³⁺ + 3 Pb (s) →    2 Al (s) + 3 Pb²⁺ occur spontaneously in aqueous solution?

            A.     yes                      B.    no