An ionic compound MX3 is prepared according to the following unbalanced chemical equation. M + X2 gives MX3, A 0.105-g sample of X2 contains 8.92 X 10^20 molecules. The compound MX3 consists of 54.47% X by mass. What are the identities of M and X, and what is the correct name for MX3? Starting with 1.00 g each of M and X2, what mass of MX3 can be prepared?

Respuesta :

Answer:

Atomic mass of 35.5 g/mol is of chlorine.

Atomic mass of 89.02 g/mol is of Yttrium.

Ytterium(III) chloride is the correct name for [tex]YCl_3[/tex].

1.835 grams of [tex]YCl_3[/tex]can be prepared.

Explanation:

[tex]2M+3X_2\rightarrow 2MX_3[/tex]

Moles of [tex]X_2[/tex] =n

Number of moleules of [tex]X_2=8.92\times 10^{20} molecules[/tex]

1 mole = [tex]6.022\times 10^{23} molecules[/tex]

[tex]n=\frac{8.92\times 10^{20} molecules}{6.022\times 10^{23} molecules}[/tex]

n = 0.001481 mole

Mass of [tex]X_2=0.105 g[/tex]

Molar mass of [tex]X_2=m[/tex]

[tex]n=\frac{Mass}{\text{Molar mass}}[/tex]

[tex]0.001481 mol=\frac{0.105 g}{m}[/tex]

m = 71 g/mol

Atomic mass of X = [tex]\frac{71 g/mol}{2}=35.5 g/mol[/tex]

Atomic mass of 35.5 g/mol is of chlorine.

The compound MX3 consists of 54.47% X by mass:

Molar mass of compound = M'

Percentage of element in compound :

[tex]=\frac{\text{number of atoms}\times text{Atomic mass}}{\text{molar mas of compound}}\times 100[/tex]

X:

[tex]54.47\%=\frac{3\times 35.5 g/mol}{M'}\times 100[/tex]

M' = 195.52 g/mol

Molar mass of compound = M'

M' = 1 × (atomic mass of M)+ 3 × (atomic mass of X)

195.52 g/mol = atomic mass of M + 3 × (35.5 g/mol)

Atomic mass of M = 89.02 g/mol

Atomic mass of 89.02 g/mol is of Yttrium.

Ytterium(III) chloride is the correct name for [tex]YCl_3[/tex].

[tex]2Y+3Cl_2\rightarrow 2YCl_3[/tex]

Moles of Yttrium = [tex]\frac{1g }{89.02 g/mol}=0.01123 mol[/tex]

Moles of chlorine gas= [tex]\frac{1 g}{71 g/mol}=0.01408 mol[/tex]

According to reaction, 3 moles of chlorine reacts with 2 moles of Y.

Then 0.01408 moles of chlorine gas will :

[tex]\frac{2}{3}\times 0.01408 mol=0.009387 mol[/tex] of Y.

This means that chlorine is in limiting amount., So, amount of yttrium (III) chloride will depend upon amount of chlorine gas.

According to reaction , 3 moles of chlorine gives 2 moles of [tex]YCl_3[/tex]

Then 0.01408 moles of chlorine will give :

[tex]\frac{2}{3}\times 0.01408 mol=0.009387 mol[/tex] of [tex]YCl_3[/tex]

Mass of 0.009387 moles of [tex]YCl_3[/tex]:

0.009387 mol × 195.52 g/mol = 1.835 g

1.835 grams of [tex]YCl_3[/tex]can be prepared.