Aballoon contains 0.76 mol n2, 0.18 mol o2, 0.031 mol he and 0.026 mol h2 at 749 mm hg. what is the partial pressure (in mm hg) of o2? give a numeric answer only, no units.

Which statement is true about hcl? (5 points) select one: a. it is a salt because it increases the concentration of metallic ions. b. it is a salt because it is formed by the reaction of an acid and a base. c. it is an acid because it increases the concentration of hydroxyl ions. d. it is an acid because it increases the concentration of hydronium ions.

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.

What is the value of the standard enthalpy of formation of an element in its most stable form?