what is the correct numerical setup for calculating the volume of h2(g) produced if the conditions are changed to STP

What is the ph of a solution with a 1.50 × 10−9 m hydroxide ion concentration?

Water (2510 g ) is heated until it just begins to boil. if the water absorbs 5.09×105 j of heat in the process, what was the initial temperature of the water?

What’s the percent by mass of carbon in c10h14n2