Question 8

buffer solutions:

keep the ph of the solution constant even when small amounts of acid or base are added

resist changes in ph when small amounts of acid or base are added

are not used up in buffer reactions and can keep reacting to adjust the ph indefinitely

have no practical uses outside of laboratory conditions

B

Explanation:

I would go with B b/c C and D are wrong. The reason C is wrong is that buffers do get used up after a while so it wont be able to react indefinitely to maintain the pH and the reason D is wrong is that there are thousands of uses for buffer ranging from your own human body to thousands and thousands of things.

In my opinion, A is not necessarily wrong because buffer's job is to keep the pH of the solution relatively constant (up to some point), but I think B is still the best answer because it describes the actual function of buffer which is to resist pH.

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.