How much of a 500g sample of potassium-42 is left after 37.2 hours if the half-life of potassium-42 is 12.4 hours.

Calculate the number of moles of ethane in 100 grams

Scientists are often interested in knowing the molar heat of combustion – the heat released during the combustion of one mole of a substance. use the periodic table to find molar masses. how many moles of ethanol are present in the sample?

What physical property of gold makes panning a useful way to get gold from streams?