MODEL Use mathematical models, in the form of sketches, example problems, or calculations, to illustrate why density is a quantity that does not depend on the size of the
sample tested

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

650.j is the same amount of energy as? 2720cal1550cal650.cal2.72cal

Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.