[finndingnemo]

"After combusting 1,321 g of metallic magnesium, 2,107 g of solid was formed. What was the mass percentage of magnesium nitride in the product mixture? Submit your response in mass percents with one decimal, without typing the unit."

I really am confused of all that is being asked, sorry.

[AWK]

When you burn magnesium in the air, not only magnesium oxide is formed, but also magnesium nitride, and you get a mixture of both. If only magnesium oxide was formed, its weight would be 2.19 g.

[chenbeier]

First of all, you should do some work by yourself.

1. Which elements (gases) mainly in the air?
2. What reaction take place if you burn something?
3. In the case of Magnesium which products are formed, develop the equation for that.
4. Develop a combinded equation containing x and y of the elements.

[Corribus]

When you burn magnesium in the air, not only magnesium oxide is formed, but also magnesium nitride, and you get a mixture of both.

Do you?

[finndingnemo]

First of all, you should do some work by yourself.

1. Which elements (gases) mainly in the air?
2. What reaction take place if you burn something?
3. In the case of Magnesium which products are formed, develop the equation for that.
4. Develop a combinded equation containing x and y of the elements.

I mean, I understand that I am burning Mg and that I have N and O also reacting there. On the other side I have Mg3N2 and MnO as the outcomes. But my calculations about the weight make no sense. Thank you for replying, though.

[AWK]

When you burn magnesium in the air, not only magnesium oxide is formed, but also magnesium nitride, and you get a mixture of both.

Do you?

True, but it is not found in general chemistry textbooks. .

[AWK]

First of all, you should do some work by yourself.

1. Which elements (gases) mainly in the air?
2. What reaction take place if you burn something?
3. In the case of Magnesium which products are formed, develop the equation for that.
4. Develop a combinded equation containing x and y of the elements.

I mean, I understand that I am burning Mg and that I have N and O also reacting there. On the other side I have Mg3N2 and MnO as the outcomes. But my calculations about the weight make no sense. Thank you for replying, though.

You need two equations for masses and moles.

[chenbeier]

When you burn magnesium in the air, not only magnesium oxide is formed, but also magnesium nitride, and you get a mixture of both.

Do you?

I did some years ago and the product given to water had a slight smell of ammonia.

[finndingnemo]

First of all, you should do some work by yourself.

1. Which elements (gases) mainly in the air?
2. What reaction take place if you burn something?
3. In the case of Magnesium which products are formed, develop the equation for that.
4. Develop a combinded equation containing x and y of the elements.

I mean, I understand that I am burning Mg and that I have N and O also reacting there. On the other side I have Mg3N2 and MnO as the outcomes. But my calculations about the weight make no sense. Thank you for replying, though.

You need two equations for masses and moles.

Could you elaborate?

I don't know how to form the correct equation to get the Mg₃N₂ and MgO. Like:

5 Mg + O₂ + N₂ = 2 MgO + Mg₃N₂?

(Look guys, I decided to take chem as my minor in university, while marketing is my major. My last chem studies were in 2008, in high school. So my knowledge is what it is. It's been only three weeks now.)

[AWK]

Write down separate reactions for oxide and nitride.

[finndingnemo]

2 Mg + 0₂ = 2 MgO or is it just Mg + O = MgO?

3Mg + N₂ = Mg₃N₂

Then what?

[AWK]

Divide the magnesium into two parts: the one in the oxide and that in the nitride (I prefer moles). Then set the second equation for the mass of the mixture.

[finndingnemo]

Ah, I give up, it's only one question in the set. But thanks for taking the time, I really appreciate it.

[Borek]

Assume x grams of Mg reacted with oxygen, and y grams of Mg reacted with nitrogen.

x+y=1.321g - this one is obvious, isn't it?

Can you express mass of the combined product mixture using x, y?

That will yield two equations in two unknowns, easy to solve.