A chemical change occurs when two or more substances react to form one or more new substances. Which of the following best completes this statement about a chemical reaction? In a chemical reaction, . . .

A. Atoms are neither created nor destroyed.

B. Some atoms from the reactants may be lost.

C. Extra atoms are always gained in the product.

D. Extra atoms are added to the product, if needed.

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.