Hydrogen is mixed with a stoichiometric amount of oxygen in a 1 L volume at 100 kPa at 300 K. All of the hydrogen is burned at constant but heat leaves the system such that the final temperature is still 300 K. What is the amount of heat released and what is the final pressure in the container?

The density of water at room temperature is less than the assumed 1.0 g/mL used in the calculations for determining the enthalpy of neutralization. How will this small (but real) assumption affect the reported enthalpy of neutralization for the strong acid-weak base reaction? Explain.

How much heat (in kj) is needed to convert 866g of ice at -15*C to steam at 146*C? (Note: The specific heat of ice is 2.03J/g*C and the specific heat of steam is 1.99J/g*C. Delta fus for H20 is 6.01 kj/mol and Hvap is 40.79kj/mol)

Calculate the pH during the titration of 25.00 mL of 0.1000 M LiOH(aq) with 0.1000 M HI(aq) after 24.2 mL of the acid have been added. Explain.

The Ka’s for H₂SeO₂ are K1 = 2.7 x 10^-3 K2 = 2.5 x 10^-7 Calculate the pH of a solution formed when 30.0 mL of 0.25 M KSeO3 is mixed with a) 1.5 mL of 0.20 M KOH b) 20.0 mL of 0.25 M HCl c) 25.0 mL of 0.20 M K₂SeO₃

I know how to calculate pH's however, I do not know when to use K1 vs K2, can you explain please?

Calculate the molarity of the following solutions.

a) 0.950 mol of Na2S in 1.85 L of solution.

___M

b) 30.9 g of MgS in 833 mL of solution.

___M

the aldrich chemical company once manufactured a technical(low purity) grade of pinene that contained 85%(+)- alpha pinene and had a specific rotation of +43. is the 15% (by mass) impurity in this product more likely to be (-)-alpha-pinene, (-)-beta-pinene, or some optically inactive substance? justify your answer with calculations.

Consider the reaction:

2SO_2(g)+O_2(g)--->2SO_3(s)

(a) If 285.5 mL of SO₂ is allowed to react with 158.9mL of O₂ (both measured at STP), what is the limiting reactant and the theoretical yield of SO₃?

(b) If 2.805g of SO₃ is collected (measured at STP), what is the percent yield for the reaction?

A steel reaction vessel at 25 oC initially contained pure NO2 at a concentration of 2.0 x 10-4 mol/L. Some of the NO2 reacted to form N2O4 as described by the following equilibrum equation:

2NO2(g) <----------> N2O4(g)

At equilibrium, the concentration of N2O4 was found to be 6.01 x 10-6 mol/L. What is the concentration-based equilibrium constant (Kc) for this reaction at 25 oC?

I know the correct answer is 170, but I'd like to know how to get there. Thanks!

2. What is the pH of 3 mM H3PO4 solution? If you wish to adjust the pH of 1 L of that solution to 7.4, how much H+ or OH— do you need (in mmol)? At pH 7.4 what is the concentration of H2PO4 —? The pKas of H3PO4 are 2.1, 7.1 and 12.3.

Problem Title: Peptide Sequencing (Intro to Biochemichemistry)

#1:

Hydrolysis of dodecapeptide P with the enzyme trypsin affords the following fragments: Pro-Thr-Phe-Phe-Tyr-Ala-Arg, Asp-Asn-Arg, His-Arg.

Hydrolysis with chymotrypsin yields: Phe, Tyr, His-Arg-Pro-Thr-Phe, Ala-Arg-Asp-Asn-Arg.

What is the amino acid sequence of P? ___

________________

#2:

Hydrolysis of nonapeptide P with the enzyme trypsin affords the following fragments: Glu-Ser-Arg, Glu-Tyr-Ser-Phe-Ala-Arg.

Hydrolysis with chymotrypsin yields: Glu-Tyr, Ser-Phe, Ala-Arg-Glu-Ser-Arg.

What is the amino acid sequence of P? ___

Consider two solutions, the first being 50.0 mL of 1.00 M CuSO4 and the second 50.0 mL of 2.00 M KOH . When the two solutions are mixed in a constant-pressure calorimeter, a precipitate forms and the temperature of the mixture rises from 21.5 ∘C to 27.7 ∘C .

From the calorimetric data, calculate ΔH for the reaction that occurs on mixing. Assume that the calorimeter absorbs only a negligible quantity of heat, that the total volume of the solution is 100.0 mL , and that the specific heat and density of the solution after mixing are the same as that of pure water.

Using the data on gross (higher) heating values (HHV), estimate the mass of CO2 emitted per: 1) 1000 SCF of methane; 2) lb of gasoline; 3) ethanol; and, 4) No. 2 heating oil. Also express your answers in mass of CO2 per million Btu of each fuel.

predict the product of the hydrolysis of (s)-4-bromo-2-pentene

quick and easy to answer!
1. suppose you are working in a busy lab with multiple people sharing a given analytical balance. if you are weighing something which you will only have to weigh once, such as weighing out a reagent onto some weigh paper, which you immediately use to make a solution. is it OK to use the balance ' tare or zero function to set the vessel tare to zero? why or why not? if not what should be done instead?
2. now suppose you are weighing something thay you will have to weigh again later. for example suppose you are weighing out some sample into a crucible. later in the procedure you will heat the sample in the crucible to partially decompose it and you will need to know the mass of the material thay remains. is it OK to use the balance's zero fun tin to set the tare to zero? why or why not. if not what should you do instead.