You find a rock that contains equal amounts of potassium-40 and argon-40. how old is it?

The excretory system,need answers for all: )

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]

You have a sample of a metal, the sample is exactly 6.02 x 1023atom, if the sample has a mass 55.85 what metal is your sample made of?