Find the molar mass of 30si if the average molar mass of si is 28.09 g/mol? ? silicon has three naturally occurring isotopes (28si, 29si, and 30si). the molar mass and natural abundance of 28si are 27.98 g/mol and 92.20%, respectively, while the molar mass and natural abundance of 29si are 28.98 g/mol and 4.67%, respectively. i'm really stuck on how to solve this, it's a practice final exam question for

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

How can carbon move from "land" to bodies of water? describe the way human impact has lead to increased levels of co2 in the atmosphere.

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.