A sample of O2 gas was collected over H2O in a 550-mL container at 21°C and a barometric pressure of 743 torr. The vapor pressure of water is 19.0 torr at that temp. How many moles of O2 were collected?

Achemistry student needs to standardize a fresh solution of sodium hydroxide. he carefully weighs out of oxalic acid , a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in of distilled water. the student then titrates the oxalic acid solution with his sodium hydroxide solution. when the titration reaches the equivalence point, the student finds he has used of sodium hydroxide solution.calculate the molarity of the student's sodium hydroxide solution. be sure your answer has the correct number of significant digits.

What human activity increases beach erosion?

The sum of the oxidation numbers in a neutral compound is always