NMR spectrometry

Question 1

if theres 2 methyls at the end of carbon chain what does it mean for the environment

Answer 1

same environment

Question 2

why is TMS used as the standard?

Answer 2

-generates one sharp peak
-unreactive , so wont affect smaple being anaylsed
-highly volatile,can be removed from sample being tested after anaylsis fairly easily
-peak always found on far right of the spectrum