# Chemistry

posted by .

A 4.5 g piece of magnesium ribbon undergoes combustion in air to produce a mixture of two ionic solids, MgO and Mg3N2. Water is added to this mixture. It reacts with the magnesium oxide to form 9.97 g of magnesium hydroxide. Assume all reactions go to completion.
A) write a balanced equation
B) how many grams of MgO are formed by the combustion of magnesium
C) how many grams of magnesium nitride are formed?

• Chemistry -

2Mg + O2 ==> 2MgO
3Mg + N2 ==> Mg3N2

If all of the 4.5 g Mg were converted to MgO, how much MgO would be formed?
4.5/24.305 = 0.185 moles Mg.
moles MgO = 0.185
grams MgO = 0.185 mols x molar mass MgO = 7.45 g

There were 9.97 g Mg(OH)2 recovered. How many g MgO is that.
moles Mg(OH)2 = 9.97/58.31 =0.171 moles
moles MgO = 0.171
g MgO = moles x molar mass = 0.171 x 40.305 = 6.89 g MgO.
So the difference between 7.46 and 6.89 must be the mass Mg3N2 formed.

• error correction Chemistry -

There were 9.97 g Mg(OH)2 recovered. How many g MgO is that.
moles Mg(OH)2 = 9.97/58.31 =0.171 moles
moles MgO = 0.171
g MgO = moles x molar mass = 0.171 x 40.305 = 6.89 g MgO.
So the difference between 7.46 and 6.89 must be the mass Mg3N2 formed.

The difference of 7.46 and 6.89 gives the difference in MgO due to Mg3N2 (not the mass of Mg3N2). So the 0.57 g difference needs to be converted to g Mg3N2.
0.57/40.305 = mols MgO = 0.0141
moles Mg3N2 = 3 x moles MgO = 3 x 0.0141 = 0.0424 and that time molar mass Mg3N2 will give grams Mg3N2.

• Chemistry -

10.4

## Similar Questions

1. ### Chemistry

Magnesium burns in air to produce magnesium oxide MgO and magnesium nitride Mg3N2. Magnesium nitride reacts with water to give ammonia. What volume of ammonia gas at 24 degrees C and 753 mmHg will be produced from 4.56 g of magnesium …
2. ### chemistry

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide. 2Mg + O2 --> 2MgO If the mass of the magnesium increases by 0.335 g, how many grams of magnesium reacted?
3. ### chem

Magnesium burns in air to produce magnesium oxide, MgO, and magnesium nitride, Mg3N2. Magnesium nitride reacts with water to give ammonia. Mg3N2(s) + 6 H2O(l) → 3 Mg(OH)2(s) + 2 NH3(g) What volume of ammonia gas at 24°C and …
4. ### Chemistry

If water is added to magnesium nitride, ammonia gas is produced when the mixture is heated. Mg3N2(s) + 3 H2O(l) => 3 MgO(s) + 2 NH3(g) If 11.1 g of magnesium nitride is treated with water, what volume of ammonia gas would be collected …
5. ### Chem 2

If we burn a strip of magnesium in air, there will be two main products, magnesium oxide and magnesium nitride. If we then treat that mixture with water, the nitride ion is converted to ammonia. After boiling away the water and ammonia, …
6. ### Science

A piece of magnesium ribbon weight 24g is burn in air an 40g magnesium oxide is formed. What mass of oxygen combined with the magnesium in this reaction
7. ### Science

When magnesium oxide (MgO) and water (H20)react, they produce magnesium hydroxide Mg(OH)2. Magnesium hydroxide is a medicine used to treat an upset stomach. The equation for this chemical change is shown below: MgO + H20 --> Mg(OH)2 …
8. ### Chemistry (Check)

Ammonia can be produced in a two-step process. First, nitrogen reacts with red-hot magnesium to form magnesium nitride. Then magnesium nitride reacts with water to form magnesium hydroxide and ammonia. A. Write each balanced chemical …
9. ### Chemistry (Check)

Ammonia can be produced in a two-step process. First, nitrogen reacts with red-hot magnesium to form magnesium nitride. Then magnesium nitride reacts with water to form magnesium hydroxide and ammonia. A. Write each balanced chemical …
10. ### chemistry

0.197g of magnesium is burned in air 2Mg + O2 ---> 2MgO However, some of the magnesium reacts with nitrogen in the air to form Magnesium nitride instead : 3Mg + N2 --->Mg3N2 So you have a mixture of MgO and Mg3N2 weighing 0.315g.Determine …

More Similar Questions