A solution was prepared by dissolving 0.0258 mol disodium phosphate in 500.0mL of deionized water. Phosphoric acid has the following pKa values: pKa1 = 2.148 , pKa2 = 7.198 , pKa3 = 12.375.

a) What was the pH of the resulting solution?

b) What was the concentration of H2PO4- in the solution?

a) Of the chemical bonding types often found in minerals, which is the strongest and which is the weakest? Why?

b) Water molecules in ice are an example of what type of bond? Explain.

Suppose that 25.14 g of ice at -8.7°C is placed in 69.18 g of water at 98.1°C in a perfectly insulated vessel. Calculate the final temperature. (The molar heat capacity for ice is 37.5 J K-1 mol-1 and that for liquid water is 75.3 J K-1 mol-1. The molar enthalpy of fusion for ice is 6.01 kJ/mol. You must answer in Kelvin, not °C.)

Potassium oxalate is a monohydrate salt that forms colorless, odorless crystals. Oxalic acid is a diprotic acid with Ka1 = 5.4 x 10-2 and Ka2 = 5.3 x 10-5 . (a) If 1.842 g potassium oxalate monohydrate is dissolved in enough water to make 100.0 mL of solution, what will be the pH of the solution? (b) What will be the equilibrium concentration of the fully protonated oxalic acid?

Calculate ΔS if 2.10 mol of liquid water is heated from 0.00 ∘C to 13.5 ∘C under constant pressure if CP,m=75.3J⋅K−1⋅mol−1.

The answer the the problem above is 7.62 J/K

The melting point of water at the pressure of interest is 0.00 ∘C, and the enthalpy of fusion is 6.010 kJ⋅mol−1. The boiling point is 100. ∘C, and the enthalpy of vaporization is 40.65 kJ⋅mol−1. Calculate ΔS for the transformation of the same amount of water

H2O(s,0.00∘C) →H2O(g,100.∘C)

Can you help me solve the second question?

A reaction of 59.5 g of Na and 48.7 g of Br2 yields 57.1 g of NaBr. What is the percent yield?

Trichloroethylene, a widely used degreasing solvent for machine parts is produced in a two-step reaction sequence. Ethylene is first chlorinated to yield tetrachloroethane, which is dehydrochlorinated to form trichloroethylene.

C2H4 (g) + Cl2 (g) ? C2H2C14 (1) + H2 (g): ?H?? = �385.76 kJ/mol

C2H2C14 (l) ? C2HCl3 (l) + HC1 (g)
The standard heat of formation of liquid trichloroethylene is �276.2 kJ/mol
(a) Use the given data and tabulated standard heats of formation of ethylene and hydrogen chloride to calculate the standard heat of formation of tetrachloroethane and the standard heat of the second reaction.
(b) Use Hess�s law to calculate the standard heat of the reaction C2H4 (g) + 2 C12 (g) � C2HCI3 (l) + H2 (g) + HCI (g)
(c) If 300 mol/h of C2HCl3 (l) is produced in the reaction of part (b) and the reactants and products are all at 25�C and I atm, how much heat is evolved or absorbed in the process? (Assume Q = ?H)

When the contents of a 1000 cubic foot container full of basketballs is mixed with the contents of a 200 cubic foot container full of ping pong balls, the mixture does not completely fill a 1200 cubic foot container. explain this result in terms of the partial molar volumes of the basketballs and ping pong balls. state any assumptions you make.

Consider a 0.487 L solution of the amino aspartic acid (0.685 M), which ahs a carboxylic acid group (pKa = 2.10), an amine group (pKa = 9.82), and a carboxylic acid side chain (pKa = 3.86). How many liters of 2.59 M NaOH would you need to add to reach the isoelectric point of the amino acid?

Upon combustion, a compound containing only carbon and hydrogen produced 0.660 g CO2 and 0.270 g H2O.

Find the empirical formula of the compound.

The osmotic pressure of an unknown substance dissolved in 100 mL of water is measured at 298 K. The concentration of this substance is 25.5 kg m–3 and the osmotic pressure is 4.50 x 104 Pa. a) Determine the molecular weight of this substance. b) Calculate the change in the freezing point of water caused by the addition of this substance. (Keep in mind that the density of a dilute aqueous solution is approximately 1 g/mL).

For the reaction shown below, K_p = 0.148 at 37

Consider a system of distinguishable particles having only three non-degenerate energy levels separated by an energy that is equal to the value kT at 25.0K. Calculate:

1) the ratio of populations in the states at a. 1.00K

2) the molecular partition function at 25.0K

3) the molar energy at 25.0K

4) the molar heat capacity at 25.0K

5) the molar entropy at 25.0K