De los siguientes compuestos, ¿cuál o cuáles de ellos presentan un par de electrones libres en el átomo central? I. SO3
II. H2O
III. NH4+

A+b→2c when the reaction begins, the researcher records that the rate of reaction is such that 1 mole of a is consumed per minute. after making changes to the reaction, the researcher notes that 2 moles of a are consumed per minute. what change could the researcher have made to effect this change?

Apeak with a retention time of 407 s has a width at half-height (w1/2) of 7.6 s. a neighboring peak is eluted 17 s later with a w1/2 of 9.4 s. a compound that is known not to be retained was eluted in 2.5 s. the peaks are not baseline resolved. how many theoretical plates would be needed to achieve a resolution of 1.5?

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. the solution was heated by burning natural gas in a bunsen burner to distill the ethanol that formed in the flask. during the distillation, the ethanol evaporated and then condensed in the receiving flask. the flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. during this experiment the following changes occurred. which of these changes involved a physical change and not a chemical change? check all that apply. 1-condensation of ethanol 2-evaporation of ethanol 3- formation of carbon dioxide gas from glucose burning of natural gas 4-formation of ethanol from glucose by yeast 5-formation of a carbon deposit inside the flask