What is the molar mass of magnesium nitride, $"Mg"_3"N"_2$, if the mass of one mole of magnesium is 24.31 g and of one mole of nitrogen is 14.01 g?

Md Ariful Islam

0 like 0 dislike
1 views
Share with your friends

1 Answers

Md Ariful Islam

Call

The idea here is that you need to use the chemical formula for magnesium nitride, $"Mg"_3"N"_2$, to calculate the mass of one mole of the compound, i.e. its molar mass.

So, magnesium nitride is an ionic compound made up of magnesium cations, $"Mg"^(2+)$, and nitride anions, $"N"^(3-)$. The subscripts used in the compound's chemical formula tell you how many ions you get in one formula unit of magnesium nitride.

In this case, you have

$"Mg"_ color(red)(3) "N"_ color(blue)(2) -> color(red)(3)"Mg"^color(blue)(2+) + color(blue)(2)"N"^color(red)(3-)$

So, one formula unit of magnesium nitride contains $color(red)(3)$ magnesium cations and $color(blue)(2)$ nitride anions.

This means that one mole of magnesium nitride will contain $color(red)(3)$ moles of magnesium cations and $color(blue)(2)$ moles of nitride anions.

Now, you know that one mole of magnesium has a mass of $"24.31 g"$. Since you get three moles of magnesium cations per mole of the compound, magnesium's contribution to the molar mass will be

$color(red)(3) color(red)(cancel(color(black)("moles Mg"^(2+)))) * "24.31 g"/(1color(red)(cancel(color(black)("mole Mg"^(2+))))) = "72.93 g"$

Likewise, you know that one mole of nitrogen has a mass of $"14.01 g"$. Since you get two moles of nitride anions per mole of the compound, nitrogen's contribution will be

$color(blue)(2) color(red)(cancel(color(black)("moles N"^(3-)))) * "14.01 g"/(1color(red)(cancel(color(black)("mole N"^(3-))))) = "28.02 g"$

Therefore, the total mass of one mole of magnesium nitride will be

$"72.93 g" + "28.02 g" = "100.95 g"$

Since this is how many grams you get per mole, you can say that the molar mass will be

$"molar mass" = color(green)(|bar(ul(color(white)(a/a)color(black)("100.95 g mol"^(-1))color(white)(a/a)|)))$

I'll leave the answer rounded to five , despite the fact that you only have four sig figs for the molar masses of the two .

0 like 0 dislike
1 views
Talk Doctor Online in Bissoy App
I did a Magnesium Oxide Lab.Magnesium often reacts with nitrogen in the air. If some of the magnesium had reacted with the nitrogen, would it make the % composition of ur sample higher or lower than it should be? Explain (Hint-Try a sample calculation).

Okay, so you've performed the classic magnesium oxide lab. I assume that you have your data, so I'll just walk you through this from a theoretical standpoint. So, you...

1 Answers 1 views
Magnesium reacts with nitrogen to form magnesium nitride. The chemical formula for this reaction is $Mg+N_2-> MgN_2$. What is the product, or what are the products, of this reaction?

As do many active metals, magnesium nitride can be formed by heating the metal (fiercely!) under dinitrogen gas: $3Mg + N_2 stackrel(Delta)rarr Mg_3N_2$ As a nitride it can by hydrolyzed...

1 Answers 1 views
How do I convert from the mass of $"25.9 g Mg"_3"N"_2$ to the mass of $"27.7 g H"_2"O"$? The reaction is magnesium nitride reacts in water to form magnesium hydroxide and ammonia.

I assume you know the chemical formulas already and are just unfamiliar with the math-writing notation here to communicate your reaction. So the reaction is: $color(red)(1)"Mg"_3"N"_2(s) + color(red)(1)"H"_2"O"(l) ->...

1 Answers 1 views
How many moles of magnesium oxide are produced by the reaction of 3.82 g of magnesium nitride with 7.73 g of water? $Mg_3N_2 + 3H_2O -> 2NH_3 3MgO$

Is it balanced? Don't trust my arithmetic. This tells us UNEQUIVOCALLY that $100.95*g$ $"magnesium nitride"$ reacts with $108.06*g$ water to give stoichiometric $"ammonia"$, and $"magnesium hydroxide"$. We have molar quantities...

1 Answers 1 views
Lithium and nitrogen react to produce lithium nitride: $6Li(s) + N_2(g) -> 2Li_3N(s)$. How many moles of lithium nitride are produced when 0.710 mol of lithium react in this fashion?

Since the given information is in moles, we need only look at the ratio between the chemicals: Six moles of Li will produce 2 moles of lithium nitride. So, the...

1 Answers 1 views
What is the number of nitrogen-based electrons in a $4.2*g$ mass of nitride anion?

And if $Z=7$, and we have $N^(3-)$, we have 10 electrons per atom, i.e. $10*e^(-)xxN_A$ electrons per mole of nitride anion. But we have a mass of $4.2*g$, which...

1 Answers 1 views
5. Lithium nitride has the chemical formula $Li_3N$. Rubidium is in the same chemical family as lithium. What is the formula of rubidium nitride?

Rubidium, an alkali metal, commonly forms $Rb^+$ salts, just as lithium commonly forms $Li^+$ salts. We would assume that the formula of rubidium nitride (if it exists!) is $Rb_3N$.

1 Answers 1 views
A mixture of magnesium carbonate and magnesium oxide of mass $12.46*g$ underwent fierce heating. After heating, there were $8.43*g$ of salt remaining. What were the masses of magnesium carbonate, and magnesium oxide in the original sample?

$MgCO_3(s)+DeltararrMgO(s) + CO_2(g)$ And we would have to heat the magnesium salt VERY fiercely to get complete decarboxylation. $"Moles of carbon dioxide LOST"$ $=$ $(4.40*g)/(44.01*g*mol^-1)$ $=0.010*mol$ And therefore in...

1 Answers 1 views
Calculate the percentages by mass of magnesium, oxygen and hydrogen in magnesium hydroxide, $Mg(OH)_2$. What is the mass of magnesium in $97.4$ $g$ of $Mg(OH)_2$?

The molar mass of $Mg(OH)_2$ is $58.3$ $gmol^-1$. The formula mass contains one mole of $Mg$ $(24.3$ $gmol^-1)$ and two moles each of $O$ $(16$ $gmol^-1)$ and hydrogen $H$ $(1$...

1 Answers 1 views
When 56.6 g of calcium is reacted with nitrogen gas, 32.4 g of calcium nitride is produced. What is the percent yield of calcium nitride in the reaction $3Ca(s) + N_2(g) -> Ca_3N_2(s)$?

$3Ca(s) + N_2(g) rarr Ca_3N_2(s)$ $"Moles of calcium metal"$ $=$ $(56.6*g)/(40.08*g*mol^-1)$ $=$ $1.41*mol$. $"Moles of calcium nitride"$ $=$ $(32.4*g)/(148.25*g*mol^-1)$ $=$ $0.219*mol$. Given the equation, $0.470*mol$ calcium nitride would be obtained...

1 Answers 1 views
X