mg + hno3 ra no

3Mg + 8HNO33Mg(NO3)2 + 2NO + 4H2O

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Word Equation

Magnesium + Nitric Acid = Magnesium Nitrate + Nitric Oxide (Radical) + Water

Three moles of Magnesium [Mg] and eight moles of Nitric Acid [HNO3] react đồ sộ form three moles of Magnesium Nitrate [Mg(NO3)2], two moles of Nitric Oxide (Radical) [NO] and four moles of Water [H2O]

Reactants

  • Magnesium - Mg

    Element 12

  • Nitric Acid - HNO3

    Hono2 Hydrogen Nitrate Engravers Acid Aqua Fortis Fuming Nitric Acid Spirit Of Niter

Products

  • Magnesium Nitrate - Mg(NO3)2

  • Nitric Oxide (Radical) - NO

    Nitric Oxide Nitrosyl Hydride Nitrogen Protoxide Nitrogen Oxide Hydroxyamine Nitrosyl Radical Nitroxyl Nitroxide Radical

  • Water - H2O

    Hydroxic Acid H₂O [Oh2] Aqua Pure Water Hydrogen Oxide Oxidane Dihydrogen Oxide

Thermodynamics

Thermodynamics of the reaction can be calculated using a lookup table.

Is the Reaction Exothermic or Endothermic?

Mg (s)3 mol0 kJ/mol-0 kJ
HNO3 (l)8 mol-173.2176 kJ/mol1385.7408 kJ
Mg(NO3)2 (s)3 mol-790.65048 kJ/mol-2371.95144 kJ
NO (g)2 mol90.24888 kJ/mol180.49776 kJ
H2O (g)4 mol-241.818464 kJ/mol-967.273856 kJ
ΣΔH°f(reactants)-1385.7408 kJ
ΣΔH°f(products)-3158.727536 kJ
ΔH°rxn-1772.986736 kJ

ΣΔH°f(reactants) > ΣΔH°f(products), ví Mg + HNO3 = Mg(NO3)2 + NO + H2O is exothermic (releases heat).

Is the Reaction Exoentropic or Endoentropic?

ΔS = Sproducts - Sreactants. If ΔS < 0, it is exoentropic. If ΔS > 0, it is endoentropic.

Mg (s)3 mol32.693776 J/(mol K)-98.081328 J/K
HNO3 (l)8 mol155.60296 J/(mol K)-1244.82368 J/K
Mg(NO3)2 (s)3 mol164.0128 J/(mol K)492.0384 J/K
NO (g)2 mol210.651848 J/(mol K)421.303696 J/K
H2O (g)4 mol188.715136 J/(mol K)754.860544 J/K
ΣΔS°(reactants)1342.905008 J/K
ΣΔS°(products)1668.20264 J/K
ΔS°rxn325.297632 J/K

ΣΔS°(products) > ΣΔS°(reactants), ví Mg + HNO3 = Mg(NO3)2 + NO + H2O is endoentropic (increase in entropy).

Is the Reaction Exergonic or Endergonic?

ΔG = Gproducts - Greactants. If ΔG < 0, it is exergonic. If ΔG > 0, it is endergonic.

Mg (s)3 mol0 kJ/mol-0 kJ
HNO3 (l)8 mol-79.9144 kJ/mol639.3152 kJ
Mg(NO3)2 (s)3 mol-589.5256 kJ/mol-1768.5768 kJ
NO (g)2 mol86.56696 kJ/mol173.13392 kJ
H2O (g)4 mol-228.588656 kJ/mol-914.354624 kJ
ΣΔG°(reactants)-639.3152 kJ
ΣΔG°(products)-2509.797504 kJ
ΔG°rxn-1870.482304 kJ

ΣΔG°(reactants) > ΣΔG°(products), ví Mg + HNO3 = Mg(NO3)2 + NO + H2O is exergonic (releases energy).

Reaction Expressions

Kc or Q = ( [Mg(NO3)2]3 [NO]2 [H2O]4 ) / ( [Mg]3 [HNO3]8 )

(assuming all reactants and products are aqueous. substitutue 1 for any solids/liquids, and Psubstance for gases.)

rate = -1/3 * (Δ[Mg] / Δt) = -1/8 * (Δ[HNO3] / Δt) = 1/3 * (Δ[Mg(NO3)2] / Δt) = một nửa * (Δ[NO] / Δt) = 1/4 * (Δ[H2O] / Δt)

(assuming constant volume in a closed system and no accumulation of intermediates or side products)

Instructions

To balance a chemical equation, enter an equation of a chemical reaction and press the Balance button. The balanced equation will appear above.

  • Use uppercase for the first character in the element and lowercase for the second character. Examples: Fe, Au, Co, Br, C, O, N, F.
  • Ionic charges are not yet supported and will be ignored.
  • Replace immutable groups in compounds đồ sộ avoid ambiguity. For example, C6H5C2H5 + O2 = C6H5OH + CO2 + H2O will not be balanced, but XC2H5 + O2 = XOH + CO2 + H2O will.
  • Compound states [like (s) (aq) or (g)] are not required.
  • You can use parenthesis () or brackets [].

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Balance Mg + HNO3 = Mg(NO3)2 + NO + H2O Using the Algebraic Method

How To Balance Mg + HNO3 = Mg(NO3)2 + NO + H2O

Xem thêm: gặp lá cơm nếp

To balance the equation Mg + HNO3 = Mg(NO3)2 + NO + 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.

a Mg + b HNO3 = c Mg(NO3)2 + d NO + f H2O

Step 2: Create a System of Equations

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

Mg:	1a	+	0b	=	1c	+	0d	+	0f
H:	0a	+	1b	=	0c	+	0d	+	2f
N:	0a	+	1b	=	2c	+	1d	+	0f
O:	0a	+	3b	=	6c	+	1d	+	1f

Step 3: Solve For All Variables

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

  • 1a - 1c = 0
  • 1b - 2f = 0
  • 1b - 2c - 1d = 0
  • 3b - 6c - 1d - 1f = 0

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

[ 1	 0	-1	 0	 0	0]
[ 0	 1	 0	 0	-2	0]
[ 0	 1	-2	-1	 0	0]
[ 0	 3	-6	-1	-1	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 = 3 (Mg)
  • b = 8 (HNO3)
  • c = 3 (Mg(NO3)2)
  • d = 2 (NO)
  • f = 4 (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.

3 Mg + 8 HNO3 = 3 Mg(NO3)2 + 2 NO + 4 H2O

Reactants Products
Mg33✔️
H88✔️
N88✔️
O2424✔️

Since there is an equal number of each element in the reactants and products of 3Mg + 8HNO3 = 3Mg(NO3)2 + 2NO + 4H2O, the equation is balanced.

Balance Mg + HNO3 = Mg(NO3)2 + NO + H2O Using Inspection

The law of conservation of mass states that matter cannot be created or destroyed, which means there must be the same number atoms at the kết thúc of a chemical reaction as at the beginning. To be balanced, every element in Mg + HNO3 = Mg(NO3)2 + NO + H2O must have the same number of atoms on each side of the equation. When using the inspection method (also known as the trial-and-error method), this principle is used đồ sộ balance one element at a time until both sides are equal and the chemical equation is balanced.

Step 1: Count the number of each element on the left and right hand sides

Reactants (Left Hand Side)Products (Right Hand Side)
ReactantsProducts
MgHNO3TotalMg(NO3)2NOH2OTotal
Mg1111✔️
H1122
N11213
O336118

Step 2: Multiply coefficients for compounds đồ sộ balance out each element

For each element that is not equal, try đồ sộ balance it by adding more of it đồ sộ the side with less. Sometimes there may be multiple compounds with that element on one side, ví you'll need đồ sộ use your best judgement and be prepared đồ sộ go back and try the other options.

  1. H is not balanced. Add 1 molecule of HNO3 đồ sộ the reactant (left-hand) side đồ sộ balance Hydrogen:
    Mg + 2HNO3 = Mg(NO3)2 + NO + H2O

    ReactantsProducts
    Mg11✔️
    H22✔️
    N23
    O68
  2. N is not balanced. Add 1 molecule of HNO3 đồ sộ the reactant (left-hand) side đồ sộ balance Nitrogen:
    Mg + 3HNO3 = Mg(NO3)2 + NO + H2O

    ReactantsProducts
    Mg11✔️
    H32
    N33✔️
    O98
  3. O is not balanced. Add 1 molecule of NO đồ sộ the product (right-hand) side đồ sộ balance Oxygen:
    Mg + 3HNO3 = Mg(NO3)2 + 2NO + H2O

    ReactantsProducts
    Mg11✔️
    H32
    N34
    O99✔️
  4. N is not balanced. Add 1 molecule of HNO3 đồ sộ the reactant (left-hand) side đồ sộ balance Nitrogen:
    Mg + 4HNO3 = Mg(NO3)2 + 2NO + H2O

    ReactantsProducts
    Mg11✔️
    H42
    N44✔️
    O129
  5. H is not balanced. Add 1 molecule of H2O đồ sộ the product (right-hand) side đồ sộ balance Hydrogen:
    Mg + 4HNO3 = Mg(NO3)2 + 2NO + 2H2O

    ReactantsProducts
    Mg11✔️
    H44✔️
    N44✔️
    O1210
  6. O is not balanced. Add 2 molecules of H2O đồ sộ the product (right-hand) side đồ sộ balance Oxygen:
    Mg + 4HNO3 = Mg(NO3)2 + 2NO + 4H2O

    ReactantsProducts
    Mg11✔️
    H48
    N44✔️
    O1212✔️
  7. H is not balanced. Add 4 molecules of HNO3 đồ sộ the reactant (left-hand) side đồ sộ balance Hydrogen:
    Mg + 8HNO3 = Mg(NO3)2 + 2NO + 4H2O

    ReactantsProducts
    Mg11✔️
    H88✔️
    N84
    O2412
  8. N is not balanced. Add 2 molecules of Mg(NO3)2 đồ sộ the product (right-hand) side đồ sộ balance Nitrogen:
    Mg + 8HNO3 = 3Mg(NO3)2 + 2NO + 4H2O

    Xem thêm: bài 8 địa 10 kết nối tri thức

    ReactantsProducts
    Mg13
    H88✔️
    N88✔️
    O2424✔️

We could not determine all the steps needed đồ sộ balance the equation using trial and error. This may mean it requires too many steps and the chemical equation is too complex đồ sộ use this method, or that the equation is invalid (e.g. has 0 or non-integer coefficients). The algebraic method is likely better suited for balancing this equation.

If you would lượt thích đồ sộ attempt đồ sộ guess the next steps, the final element counts in the balanced equation should be:

3Mg + 8HNO3 = 3Mg(NO3)2 + 2NO + 4H2O

ReactantsProducts
Mg33✔️
H88✔️
N88✔️
O2424✔️

Practice Balancing