Explanation:
Moles of N2 = 35.0g / (28g/mol) = 1.25mol
Moles of H2 = 60.0g / (2g/mol) = 30.0mol
Since 1.25mol * 3 < 30.0mol, nitrogen is limiting.
Moles of NH3 = 1.25mol * 2 = 2.50mol.
Mass of NH3 = 2.50mol * (17g/mol) = 42.5g.
30.0mol - 1.25mol * 3 = 26.25mol.
Excess mass of H2
= 26.25mol * (2g/mol) = 52.5g.
First we need to find the number of moles that 43.9g of gallium metal is. We can do this by finding the molar weight of gallium and cross-multiplying to cancel out units:

So we are dealing with 0.63 moles of gallium metal.
We can take from the balanced equation that 4 moles of gallium metal will react completely with 3 moles of oxygen gas. We can take this ratio and make a proportion to find the amount of oxygen gas, in moles, that will react completely with 0.63 moles of gallium metal:

Cross multiply and solve for x:


So now we know that 0.47 moles of oxygen gas will react with 43.9g of gallium metal.
Answer:
Group 12
Explanation:
Group 12 is also called a transition metal group. This group in the periodic table lies in between the groups or tables. These metals are classified as the transition metal in the table.
These metals are found from the group number 3 to 12. In the periodic table, These transition elements are ductile and malleable. These metal conduct heat and electricity.
These elements are generally called dense and less to react to the alkaline metal. Iron, copper-silver, gold is the most important transition metal.