I have 10g of magnesium oxide that I heat to make 6g of magnesium and oxygen. how much oxygen is made? What kind of change is this, physical or chemical? why did you pick your answer? Explain in 2 sentences
The study of chemistry is called "Gateway" where you live? That's a new one on me!
I can tell you that you do not make oxygen by heating MgO. You make MgO by heating Mg and O2. However, in the spirit of the question, I will answer as written. This is the Law of Conservation of Mass. You started with 10 g so you must end up with 10 g.
.....MgO ==> Mg + O2
.....10......6.....? so ? must be 4. I did NOT check to see if the chemistry is right since I don't have my calculator with me.
To find the mass of oxygen made, you need to subtract the mass of magnesium (6g) from the initial mass of magnesium oxide (10g). Therefore, the mass of oxygen made is 10g - 6g = 4g. This is a chemical change because magnesium oxide undergoes a chemical reaction (decomposition) where it breaks down into its constituent elements, magnesium and oxygen, with a change in chemical composition.
I arrived at my answer by recognizing that the mass of oxygen can be determined by the change in mass between magnesium oxide and magnesium, as the only other element involved is oxygen. Additionally, since the reaction involves the formation of new substances with different properties, it indicates a chemical change rather than a physical change.