Physical Chemistry Answers

NH4ClO3 lewis structure

The total volume of seawater is 1.5 x 1021 L. Assume that seawater contains 3.1 percent sodium chloride by mass and that its density is 1.03 g/mL. Calculate the total mass of sodium chloride in kilograms and in tons. (1 ton = 2000 lb; 1 lb = 453.6 g.)

An atom contains one more proton than, but the same number of neutrons as, an atom of 29Si. Identify the atom and its nucleon number.

20mL of a gas at 200K is heated until the new volume is 55mL. What is the final temperature of the gas?

Use the data to find another value for the enthalpy of buta-l , 3 —diene.
Bond energies Enthalpies of atomisation
C-H 413 KJ/mol C 715 KJ/mol
346 KJ/mol H 218 KJ/mol
610 KJ/mol

The molar enthalpy of combustion of carbon, hydrogen and buta-l ,
3-diene (CH2 = CHCH = CH2) are - 394, - 288 and - 2542 KJ/mol respectively. By
using a suitable thermochemical diagram or otherwise find the enthalpy of formation of buta-1, 3-diene.

Give the precise thermochemical equation to which the following statements refer.
(i) The standard enthalpy of formation Of methane is - 74.8 K J/mol
(ii) The mean bond energy of C - H bond in methane is 413 KJ/mol
(iii) The enthalpy of atomization of carbon is 715 KJ/mol

Suppose you prepared a Vitamin C stock solution by dissolving 500 mg of ascorbic acid in 60 mL distilled water.

To create solution A, you need to have the following concentrations: 50 mg, 75 mg, 100 mg and 500 mg.

You take 10 mL of the 500 mg concentration stock solution, how much water will you need to dilute to have a 50 mg concentration? How about 75? 100? 500?

(a) Draw a well-labeled Bom-Haber cycle for the formation of one mole of magnesium oxide (solid) identifying all the standard energy changes involved.

20 g of an ideal gas contains only atoms of S and O occupies 5.6 L at 1 atm and 273 K. What is the mol. wt. of gas?