Answer:
The balanced chemical equation is given as:

Explanation:
When magnesium metal burns in presence of oxygen it gives white color powdered compound called magnesium oxide.
The balanced chemical equation is given as:

According to reaction, 2 moles of magnesium metal when reacts with 1 mole of oxygen gas it gives 2 moles of solid magnesium oxide.
Answer:
When the two gases are mixed, the ammonium chloride precipitates in the tube walls.
Explanation:
This is the reaction:
HCl (g) + NH₃(g) → NH₄Cl (s) ↓
As the product formed is solid at room temperature, a suspension is first formed in the internal air of the tube that appears as a cloud. Afterwards it finally precipitates into the walls forming a white layer
Do you have the picture of the data?
Chemical change or process
The reactants are all the formulas to the left of the arrow, which are:
hcI(aq) nahco3(aq)