Which of these substances are compounds? how do you know?
a. salt (nacl)
b. nitrogen (n)
c. helium (he)
d. water (h2o)

At 450 mm hg a gas has a volume of 760 l, what is its volume at standard pressure

Remember to use the proper number of significant figures and leading zeros in all calculations. gelatin has a density of 1.27 g/cm³. if you have a blob of gelatin dessert that fills a 2.0 liter bottle, what is its mass? 2540 g2500 g3.9 x 10-43.937x 10-4

Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. an industrial chemist studying this reaction fills a 25.0l tank with 4.5 mol of sulfur dioxide gas and 4.5 mol of oxygen gas at 30.°c. he then raises the temperature, and when the mixture has come to equilibrium measures the amount of sulfur trioxide gas to be 1.4 mol. calculate the concentration equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. round your answer to 2 significant digits.