Which of these does not involve a chemical change? a. red delicious apples fell to the ground. b. cocaine causes the release of norepinephrine from nerve cells. c. mercury is used in barometers because it has a high density. d. antacids often an upset stomach

c. Mercury is used in barometers because it has a high density

Explanation:

Chemical change -  

It refers to any change in a chemical process , where there is formation of any new substance , is referred to as a chemical change .

The indication of any chemical change is the formation of some new substance.

Hence, from the question,

The process which does not involve chemical change is  -

The use of mercury in barometer , to measure pressure , in this process no new substance is formed i.e. , now change in mercury.

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.

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