You have a 15 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 7.72. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 6.31. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 15 mL sample. Remember to use significant figures in your answer.
acetycholine in original sample:

8. what happens to matter during a chemical reaction

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.

Air pressure is measured in pascals. for a professional american football game, the ball should be inflated to about 90,000 pascals. scientists studied the effects of air temperature on the pressure inside american footballs by taking these steps: 1. prepare 100 footballs. 2. measure each football's air pressure. 3. divide footballs into 10 groups. 4. place the groups in different lockers cooled to different air temperatures. 5. after 12 hours, remove the footballs from lockers. 6. measure each football's pressure again. 7. compare the new pressures to the starting pressures. what two terms best describe the variable "air pressure inside the football" in this experiment? independent, qualitative independent, quantitative dependent, qualitative dependent, quantitative