Magnesium metal reacts with gaseous oxygen in a combination reaction. Write a balanced equation to describe this reaction. Include states of matter in your answer. Click in the answer box to open the symbol palette.

2Mg (s) + O2 (g) > 2MgO (s)

Explanation:

Lets write the equation of the reaction.

Mg(s) + O2 (g) > MgO (s)

Counting the number of atoms for each element we have:

Left hand side: Mg =1 O = 2

Right hand side : Mg = 1, O =2

To balance this equation input "2" as coefficient for "MgO" on the right hand side and "2", as coefficient for "Mg" on the left hand side of the equation. Hence our balanced equation will be

2Mg (s) + O2 (g) > 2MgO (s)

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2