2. circle the letter of each sentence that is true about numbers expressed in
scientific notation.
a. a number expressed in scientific notation is written as the product of a
coefficient and a power of 10.
b. the power of 10 is called the exponent.
c. the coefficient is always a number greater than or equal to one and less
than ten.
d. for numbers less than one, the exponent is positive.

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.