Classe Khan Academy Fre...
11.) Which of these statements about molecules is true?
a) All molecules contain atoms of only one element.
b) Two or more molecules can combine to form an atom.
c) The elements in any molecule are always present in equal proportions.
d) The atoms in a molecule cannot be separated from each other by physical means.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

How do i turn 2 s into one in the products

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.