I was doing a lab today in chemistry, and I do not know if I got my measurements correctly. My teacher gave us a strip (probably 5inches) of Mg. We measured it, and then after that, we had to burn it, and measure the mass of it after it was burn. Would the burned Mg have more mass or less mass?
How do you suppose Mg burns. Don't most things need oxygen to burn? Did you get a white powder? What do you think the white powder was?
Yeah, We got a white powder. So I guess our new substance would be MgO. I think it should weigh more. Am I right? but it shouldn't weigh much more right? probably around .05g more? Does that sound about right?
Also, she asked me to write any chemical changes that occurred. If I mention the color changes, the texture, and the mass, would that be consider chemical changes?
Color, texture, mass are all physical changes. Changing to MgO is a chemical change and you can write an equation for it.
Mg + O2 ==> MgO
You need to balance it.
You can see from the equation that the amount it changes in mass is a function of how much Mg you started with. 24.3 grams Mg (a mole) will gain 16 g oxygen (a mole of oxygen atoms).
What would be consider a chemical change besides MgO?
I'm thinking maybe the sparked it made would be a chemical change when it was being burned. Is that another a example of a chemical change? I need one more chemical change. So far I got:
1. Changed from Mg to MgO
2. Made spark when burning
3.
I would consider the spark (actually an extremely bright light) a byproduct of the oxidation process. It is an exothermic reaction. Any reaction that Mg goes through is a chemical change. Another change that took place when you burned the Mg ribbon was its combination with nitrogen of the air to produce magnesium nitride.
Mg + N2 ==> Mg3N2. Again, you need to balance the equation.