How many moles are there in 3.9 grams of potassium

The big bang nucleosynthesis theory states that elements were produced in the first few minutes of the big bang while elements have their origins in the interiors of stars, forming much later in the history of the universe.

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?

If 22.5 liters of oxygen reacted with excess of hydrogen, how many liters of water vapor could be produced?