A sample of element Z, which has two isotopes, is made up of 75% Z-12 and 25% Z-13. Calculate the average atomic mass. Round your answer to TWO PLACES after the decimal. Enter your answer as a number (no units)

What will most likely happen in the absence of a cell membrane? a) photosynthesis will not take place. b) the cell will not store food, water, nutrients, and waste. c) energy will not be released during cellular respiration. d) substances will pass in and out of the cell in an uncontrolled manner.

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

Ok, so i have 2 questions. try to answer them both: (the topic is fire) 1) how can you represent the chemical reaction of fire? 2) what kind of bond is formed in this chemical reaction