1. Equal
2. Properties
3. Heat
4. Reverse
After 3 half life periods you would have 5 grams of krypton left because half of 40 is 20 half of 20 is 10 and half of 10 is 5
Always use this method !!! always
Did u mean mass of potassium nitrate or the mass of nitrogen in potassium nitrate
Mass is often the most common and weight is its close to that but I'd go with mass
