Question

Подберите коэффициенты методом электронного баланса и укажите в ответе число принятых электронов:_Cu + _HNO₃ → _Cu(NO₃)₂ + _NO₂↑ + _H₂O

Answer 1

Cu+4HNO3=Cu(NO3)2+2NO2+2H2O
Cu(0)-2e=Cu(+2)  |1
N(+5)+1e=N(+4)  |2
Cu восстановитель
HNO3 окислитель

Answer 2

Balancing the Chemical Equation Using the Electron Balance Method

To balance the chemical equation Cu + HNO₃ → Cu(NO₃)₂ + NO₂ + H₂O using the electron balance method, we need to follow these steps:

1. Write down the unbalanced equation. 2. Identify the oxidation states of the elements involved. 3. Apply the electron balance method to balance the equation.

Unbalanced Chemical Equation

The unbalanced chemical equation is: Cu + HNO₃ → Cu(NO₃)₂ + NO₂ + H₂O

Oxidation States of Elements

- The oxidation state of copper (Cu) is 0 in its elemental form. - The oxidation state of nitrogen (N) in HNO₃ is +5, and in NO₂, it is +4. - The oxidation state of oxygen (O) in HNO₃ is -2, and in NO₂ and H₂O, it is -2.

Balancing the Equation Using the Electron Balance Method

1. First, let's balance the atoms in the equation: - There are 1 Cu atom on the left and 1 Cu atom on the right, so Cu is already balanced. - There are 1 N atom on the left and 2 N atoms on the right, so we need to balance the N atoms. - There are 3 O atoms on the left and 6 O atoms on the right, so we need to balance the O atoms. - There are 1 H atom on the left and 2 H atoms on the right, so we need to balance the H atoms.

2. Now, let's balance the charges using the electron balance method: - The oxidation state of Cu does not change in the reaction, so it does not contribute to the electron balance. - The oxidation state of N changes from +5 to +4, indicating a gain of 1 electron per N atom. - The oxidation state of O does not change in the reaction, so it does not contribute to the electron balance. - The oxidation state of H does not change in the reaction, so it does not contribute to the electron balance.

Balanced Chemical Equation and Number of Electrons Transferred

The balanced chemical equation is: 3Cu + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O

The number of electrons transferred can be calculated based on the change in oxidation state of nitrogen: - Each nitrogen atom changes from +5 to +4, indicating a gain of 1 electron per nitrogen atom.

Therefore, the number of electrons transferred in the balanced chemical equation is 8.