Author: Anonymous

The concentration of urea in a solution prepared by dissolving 16 g of urea in 25g of H2O is ________% by mass.  YOU MUST SHOW YOUR WORK FOR THIS PROBLEM

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. YOU MUST SHOW YOUR WORK FOR THIS PROBLEM                         Bond:      C≡C      C-C       H-I       C-I       C-H    D (kJ/mol):       839       348       299       240       413

Which hydroxides are weak bases? 

What is the molal concentration of potassium bromide in a solution prepared by dissolving 2.27 g of potassium bromide in 897 g of water? YOU MUST SHOW YOUR WORK FOR THIS PROBLEM

As a gaseous element vaporizes, the atoms become ________ and they have ________ attraction for one another.

A sample of gas originally at 25 °C and 1.00 atm pressure in a 2.5 L container is subject to a pressure of 0.85 atm and a temperature of 15 °C. The final volume of the gas is ________ L. YOU MUST SHOW YOUR WORK FOR THIS PROBLEM

The total number of π bonds in the H—C≡C—C≡C—C≡N molecule is ________.

The concentration (M) of HCl in a solution prepared by dissolving 5.5 g of HCl in 200 g of C2H6O is ________ M. The density of the solution is 0.79 g/mL. YOU MUST SHOW YOUR WORK FOR THIS PROBLEM

A 17.2 g sample of potassium chlorate is dissolved in 250 g of water at 65 °C. The solution is cooled to 30.0 °C and no precipitate is observed. This solution is ________.

 Round the number 3456.5 to two significant figures.