# fe3o4 + hno3 = fe(no3)3 + no2 + h2o

To balance the equation Fe3O4 + HNO3 = Fe(NO3)3 + NO2 + H2O using the algebraic method step-by-step, you must have experience solving systems of linear equations. The most common methods are substitution/elimination and linear algebra, but any similar method will work.

### Step 1: Label Each Compound With a Variable

Label each compound (reactant or product) in the equation with a variable đồ sộ represent the unknown coefficients.

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a Fe3O4 + b HNO3 = c Fe(NO3)3 + d NO2 + f H2O

### Step 2: Create a System of Equations

Create an equation for each element (Fe, O, H, N) where each term represents the number of atoms of the element in each reactant or product.

```Fe:	3a	+	0b	=	1c	+	0d	+	0f
O:	4a	+	3b	=	9c	+	2d	+	1f
H:	0a	+	1b	=	0c	+	0d	+	2f
N:	0a	+	1b	=	3c	+	1d	+	0f

```

### Step 3: Solve For All Variables

Use substitution, Gaussian elimination, or a calculator đồ sộ solve for each variable.

• 3a - 1c = 0
• 4a + 3b - 9c - 2d - 1f = 0
• 1b - 2f = 0
• 1b - 3c - 1d = 0

Use your graphing calculator's rref() function (or an online rref calculator) đồ sộ convert the following matrix into reduced row-echelon-form:

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```[ 3	 0	-1	 0	 0	0]
[ 4	 3	-9	-2	-1	0]
[ 0	 1	 0	 0	-2	0]
[ 0	 1	-3	-1	 0	0]
```

The resulting matrix can be used đồ sộ determine the coefficients. In the case of a single solution, the last column of the matrix will contain the coefficients.

Simplify the result đồ sộ get the lowest, whole integer values.

• a = 1 (Fe3O4)
• b = 10 (HNO3)
• c = 3 (Fe(NO3)3)
• d = 1 (NO2)
• f = 5 (H2O)

### Step 4: Substitute Coefficients and Verify Result

Count the number of atoms of each element on each side of the equation and verify that all elements and electrons (if there are charges/ions) are balanced.

Fe3O4 + 10 HNO3 = 3 Fe(NO3)3 + NO2 + 5 H2O

Reactants Products Fe 3 3 ✔️ 34 34 ✔️ 10 10 ✔️ 10 10 ✔️

Since there is an equal number of each element in the reactants and products of Fe3O4 + 10HNO3 = 3Fe(NO3)3 + NO2 + 5H2O, the equation is balanced.