# Homework Help: Chemistry - analyzing equations

1. Jul 17, 2008

### Quincy

1. The problem statement, all variables and given/known data
4FeCr2O7 + 8K2CO3 + O2 --> 2Fe2O3 + 8K2CrO4 + 8CO[sub2[/sub]

How many grams of iron (II) dichromate are required to produce 44.0 grams of carbon dioxide?

2. Relevant equations

3. The attempt at a solution

79.925 grams of iron (II) dichromate

2. Jul 17, 2008

### Staff: Mentor

Strange reaction and strange reactant though. If you ask me, there is no such thing as iron (II) dichromate.

3. Jul 17, 2008

### Quincy

Nevermind my first answer, I misinterpreted the problem, this is my new answer:

Since it takes takes 4 moles of iron (II) dichromate to produce 8 moles of carbon dioxide, it would take 0.5 moles of iron (II) dichromate to produce 1 mole of carbon dioxide (1 mole of CO2 = 44 g). And 0.5 moles of iron (II) dichromate = 109.92 grams of iron (II) dichromate (answer).

-- I don't really know what I'm doing btw; these are questions from my pre-AP Chem summer assignment and I'm bookless and haven't done any chemistry for about 1 1/2 years.

4. Jul 18, 2008

### Staff: Mentor

Your approach is OK, just numbers are wrong. What have you used for molar mass of iron (II) dichromate?

5. Jul 18, 2008

### Quincy

molar mass of iron (II) dichromate = 271.85 g

271.85/2 = 135.93 g... nevermind my other answer, is 135.93 g correct?

6. Jul 21, 2008

### Staff: Mentor

135.9 g is OK. Sorry for the late answer.

7. Jul 24, 2008

### Quincy

molar mass 4FeCr2O7 = 1087.4 g

molar mass 8CO2 = 352.08 g

1087.4/352.08 = x/44 ~ x = 135.9 g

^ Is it possible to use proportions for these type of problems?

8. Jul 24, 2008