P help Why is tetra methyl silane (CH3)4Si is used as a reference sample in NMR spectrometry?? I mean what are the properties of TMS that make it suitable for being used as a reference sample??

Select all of the methods through which a drug can enter your body. injection swallowing inhalation absorption

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Many pharmaceutical drugs are organic compounds that were originally synthesized in the laboratory. which two scientific disciplines are bridged by pharmaceutical drugs? chemistry and forensics chemistry and medicine biology and forensics biology and criminology