Which of the following statements about the ph scale is true?

a. acids, which have lower concentrations of hydronium ions than bases, are found from 14 and down to 7.
b. acids, which have higher concentrations of hydronium ions than bases, are found from 0 and up to 7.
c. bases, which have higher concentrations of hydronium ions than acids, are found from 14 and down to 7.
d. bases, which have higher concentrations of hydronium ions than acids, are found from 0 and up to 7.

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.

Straightforward questions answered in the powerpoint slidesreaction: heating the starting materials under refluxwhat does it mean to heat under reflux? why do we choose water as the reflux solvent? what are boiling chips used for? why do we put a condenser on top of the reaction? why do we add heat and let the reaction stir for 30 minutes? why do we add sulfuric acid to the reaction after it cools as opposed to when it’s still hot? separation: filtration of precipitatewhy don’t we do an aqueous and organic extraction in the separatory funnel? why do you rinse the salicylic acid on the filter with ice cold water? purification: recrystallization of salicylic acid (no hot filtration needed)what is the difference in the amount of room temperature water vs. boiling water needed to dissolve the salicylic acid (assume a 1.2 gram yield of salicylic acid)? remember, in the lab if you need x ml of boiling water to dissolve a solid, then you should add a little more (definitely no more than 1.5 times the theoretical amount) to ensure it doesn’t recrystallize prematurely.analysis: melting point of salicylic acidwhat can you conclude if the melting point of the salicylic acid you just synthesized is 152-155oc and the 1: 1 mix of your product and “synthetic” salicylic acid is 151-154oc?

Using the first volume and temperature reading on the table as v1 and t1, solve for the unknown values in the table below. remember to use the rules of significant figures when entering your numeric response.