Limiting Reagents With 3 Reactants

  • Thread starter xChee
  • Start date
In summary, to find the limiting reagent in a chemical reaction with multiple reactants, first convert all the given grams into moles. Then, write the ratio of theoretical moles to actual moles for each compound and divide each ratio by its denominator to get a denominator of 1. The compound with the lowest ratio is the limiting reagent.
  • #1
xChee
15
0

Homework Statement



So my test is tomorrrow, and I have troubles with limiting reagents, I can get them right sometimes with the 2 reactant questions, but not always with 3... so the question is

Q: What mass of phosphorus (P4) is produced when 41.5g of calcium phosphate, 26.5g of silicon diioxide, and 7.80g of carbon are reacted according to the eqation:

2Ca3(PO4)2 + 6SiO2 + 10C -> P4 + 6CaSiO3 + 10CO


Homework Equations



n=m/M

The Attempt at a Solution



I've checked that the equation is balanced
and I calculated the moles of 2Ca3(PO4)2 which is 0.1337 mols, 0.441 mols for 6SiO2 and 0.0649 mols for 10C.

after this idk what ratios to use to calculate what...
 
Physics news on Phys.org
  • #2
No matter how many reactants, the correct answer is always the one giving the lowest amount of products.
 
  • #3
xChee said:

Homework Statement



So my test is tomorrrow, and I have troubles with limiting reagents, I can get them right sometimes with the 2 reactant questions, but not always with 3... so the question is

Q: What mass of phosphorus (P4) is produced when 41.5g of calcium phosphate, 26.5g of silicon diioxide, and 7.80g of carbon are reacted according to the eqation:

2Ca3(PO4)2 + 6SiO2 + 10C -> P4 + 6CaSiO3 + 10CO

Homework Equations



n=m/M

The Attempt at a Solution



I've checked that the equation is balanced
and I calculated the moles of 2Ca3(PO4)2 which is 0.1337 mols, 0.441 mols for 6SiO2 and 0.0649 mols for 10C.

after this idk what ratios to use to calculate what...

Ok. First, convert all the grams given into moles.

Then, write the ratio of theoretical moles to actual moles for each compound. Finally, for each ratio, divide the whole ratio by its denominator so all the ratios have a denominator of 1. Then see which is the lowest.

Assuming you have all the grams to moles converted properly, you get this:

0.06685/1 Ca3(PO4)2

0.0735/1 SiO2

0.00649/1 C

Since 0.00649 is the least for 1 mol, then Carbon is the limiting reagent.
 

Related to Limiting Reagents With 3 Reactants

1. What is a limiting reagent?

A limiting reagent is the reactant in a chemical reaction that is completely consumed first, thereby limiting the amount of product that can be formed.

2. How do I determine the limiting reagent when there are three reactants?

To determine the limiting reagent in a reaction with three reactants, you need to compare the mole ratios of each reactant to the product. The reactant with the smallest mole ratio is the limiting reagent.

3. Can there be more than one limiting reagent in a reaction with three reactants?

Yes, it is possible for there to be more than one limiting reagent in a reaction with three reactants. This occurs when the mole ratios of two or more reactants are equal and are both smaller than the mole ratio of the third reactant.

4. How does the limiting reagent affect the amount of product formed?

The limiting reagent determines the maximum amount of product that can be formed in a reaction. Once the limiting reagent is completely consumed, the reaction will stop and no more product can be formed.

5. Can the amount of limiting reagent be increased to produce more product?

No, the amount of limiting reagent cannot be increased to produce more product. The amount of product formed is limited by the amount of limiting reagent present in the reaction.

Similar threads

Help with a question regarding Gravimetric Calculations
    • Biology and Chemistry Homework Help
Replies
1
Views
3K
How Much P4S10 Can Be Made from 10g P4 and 30g S8?
    • Biology and Chemistry Homework Help
Replies
2
Views
4K

Hot Threads

Recent Insights

Back
Top