Question

1.Расставьте коэффициенты методом электронного баланса. Укажите окислитель и восстановитель: C + HNO3 =CO2 + NO + H2O 2.Напишите молекулярные и полные ионные уравнения реакций, соответствующие сокращенным; Ca2+ + CO32- =CaCO3

Answer 1

3C +HNO3 = 3CO2↑ + 4NO↑ + 2H2O
Восстановление: NO3− + 4H+ + 3e− = NO + 2H2O
 Окисление: C + 2H2O − 4e− = CO2 + 4H+  

Answer 2

3C + 4HNO3 =3CO2 + 4NO + 2H2O
Ca(NO3)2+Na2CO3=2NaNO3+CaCO3
Ca(2+)+2NO3(-)+2Na(+)+CO3(2+)=2Na(+)+2NO3(-)+CaCO3
Ca2+ + CO32- =CaCO3

Answer 3

Balancing the Equation: C + HNO3 = CO2 + NO + H2O

To balance the equation C + HNO3 = CO2 + NO + H2O using the method of electronic balancing, we need to ensure that the number of atoms of each element is the same on both sides of the equation.

Let's start by counting the number of atoms for each element on both sides of the equation:

Left side (reactants): - Carbon (C): 1 atom - Hydrogen (H): 1 atom - Nitrogen (N): 1 atom - Oxygen (O): 3 atoms

Right side (products): - Carbon (C): 1 atom - Hydrogen (H): 2 atoms - Nitrogen (N): 1 atom - Oxygen (O): 3 atoms

To balance the equation, we can follow these steps:

Step 1: Balance the atoms of the most complex molecule first. In this case, it is HNO3.

Left side (reactants): - Carbon (C): 1 atom - Hydrogen (H): 1 atom - Nitrogen (N): 1 atom - Oxygen (O): 3 atoms

Right side (products): - Carbon (C): 1 atom - Hydrogen (H): 2 atoms - Nitrogen (N): 1 atom - Oxygen (O): 3 atoms

Step 2: Balance the atoms of the remaining molecules.

Left side (reactants): - Carbon (C): 1 atom - Hydrogen (H): 1 atom - Nitrogen (N): 1 atom - Oxygen (O): 3 atoms

Right side (products): - Carbon (C): 1 atom - Hydrogen (H): 2 atoms - Nitrogen (N): 1 atom - Oxygen (O): 3 atoms

Since the number of atoms for each element is already balanced, the equation is already balanced.

Therefore, the balanced equation is: C + HNO3 = CO2 + NO + H2O.

Now, let's determine the oxidizing agent and the reducing agent in this reaction.

In the given equation, C is oxidized from an oxidation state of 0 to +4 in CO2, while HNO3 is reduced from an oxidation state of +5 to +2 in NO.

Therefore, in the reaction C + HNO3 = CO2 + NO + H2O, C is the reducing agent and HNO3 is the oxidizing agent.

Molecular and Ionic Equations: Ca2+ + CO32- = CaCO3

The given equation is Ca2+ + CO32- = CaCO3.

To write the molecular equation, we simply write the reactants and products as they are:

Molecular Equation: Ca2+ + CO32- = CaCO3

To write the ionic equation, we need to separate the reactants and products into their respective ions:

Ionic Equation: Ca2+ + CO32- = Ca2+ + CO32-

Since the Ca2+ and CO32- ions appear on both sides of the equation, they cancel out, leaving us with:

Ionic Equation (simplified): 0 = 0

In this case, the ionic equation is simplified to show that there is no net ionic reaction occurring. The Ca2+ and CO32- ions remain unchanged in the reaction, resulting in no overall change.

Therefore, the molecular equation and the simplified ionic equation for the reaction Ca2+ + CO32- = CaCO3 are:

Molecular Equation: Ca2+ + CO32- = CaCO3 Ionic Equation (simplified): 0 = 0