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Mass Limiting Stoichiometry Problem

(ICE BOX METHOD)

Here are the Rules from the other Page

STEP1= SET UP the ICE Box

STEP 2- Find the moles, This is where you have to problem solve.

STEP 3- Find X, find the moles of everything

STEP 4- Answer the questions, convert moles to mass

Mercury and bromine will react with each other to produce mercury(II) bromide.

Hg(l) + Br₂(l) --> HgBr₂(s)
 

(a) What mass of HgBr₂ is produced from the reaction of 9.80 g Hg and 12.0 g Br₂? What mass of which reactant is left unreacted?

(b) What mass of HgBr₂ is produced from the reaction of 5.50 mL of mercury (density = 13.6 g/mL) and 5.50 mL bromine (density = 3.10 g/mL)?

A)

STEP1= SET UP the ICE Box

STEP 2- Find the moles, This is where you have to problem solve.

Hg          9.80g Hg (1mol/200.59g)=0.0489mol Hg

Br₂         12.0 Br₂ (1mol/159.8g)=0.075mol Br₂

STEP 3- Find X, find the moles of everything

If Hg   0.0489mol -X=O;  X=0.0489

If  Br₂   0.075mol -X=0;  X= 0.075

Therefore Hg is Limiting and X=0.0489 (it is smaller)

STEP 4- Answer the questions, convert moles to mass

What mass of HgBr₂ is produced?  0.0489mol x (360.3g/mol)=17.6g HgBr₂

What mass of which reactant is left unreacted? 0.026mol x (159.8g/mol)=4.12g Br₂

_B)

What mass of HgBr₂ is produced from the reaction of 5.50 mL of mercury (density = 13.6 g/mL) and 5.50 mL bromine (density = 3.10 g/mL)?

STEP1= SET UP the ICE Box

STEP 2- Find the moles, This is where you have to problem solve. You needed to use density to find mass, then convert to moles.

Hg         5.50mL(13.6g/mL)=74.8g Hg          74.8g Hg (1mol/200.59g)=0.373mol Hg 

Br₂        5.50 mL (3.10/mL)=1.77g Br₂         1.77g Br₂(1mol/159.8g)=0.0111mol Br₂

STEP 3- Find X, find the moles of everything

If Hg is limiting      0.373mol -X=O;  X=0.373

If  Br₂ is limiting    0.0111mol -X=0;  X= 0.0111

Therefore  Br₂ is Limiting and X=0.0111 (it is smaller)

STEP 4- Answer the questions, convert moles to mass

What mass of HgBr₂ is produced?   0.0111mol HgBr₂(360.3g/mol)= 4.00g HgBr₂

On to The Stoichiometry of Product Formation and Percent Yield

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