Energy is required to produce a chemical change during
(1) chromatography
(2) electrolysis
(3) boiling
(4) melting

You are making a solution of calcium chloride dissolved in water. you add solid, stir, and it dissolves. you add just a spatula tip full, stir, and the solid does not dissolve. how could you describe the solutions before and after adding the spatula tip amount

Calculate the number of moles of ethane in 100 grams

In which situation can a mixture always be called a solution