Complete and balance each of the following equations for gas-evolution reactions. HNO3(aq) + Li2S produces ? Express your answer as a chemical equation. Identify all of the phases in your answer.
2HNO3(aq) + Li2S(s) ==> H2S(g) + 2LiNO3(aq)
2HNO3(aq) + Li2S(aq) ==> H2S(g) + 2LiNO3(aq)
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To balance the equation and determine the products for the gas-evolution reaction between HNO3(aq) and Li2S, we need to identify the possible gas-forming products.
The cations in HNO3 are H+ and Li+, while the anions are NO3- and S2-. Since H+ is a weak acid, it does not typically react with most anions to produce a gas. However, S2- can react with H+ to produce H2S gas. Therefore, we can expect H2S gas to be one of the products in this reaction.
Now let's balance the equation step-by-step:
1. Balancing the non-oxygen and non-hydrogen atoms:
HNO3 + Li2S → H2S + ???
2. Balancing the hydrogen atoms:
HNO3 + Li2S → H2S + H2O
3. Balancing the oxygen atoms:
We can see that HNO3 has one oxygen atom, while H2S has no oxygen atoms. Therefore, we need to add water (H2O) to balance the oxygen atoms. In this case, we need to add three water molecules (3H2O).
HNO3 + Li2S → H2S + 3H2O
Now the equation is balanced and the gas-evolution reaction between HNO3(aq) and Li2S can be expressed as:
HNO3(aq) + Li2S(s) → H2S(g) + 3H2O(l)
The phases are indicated in parentheses: (aq) for aqueous solution, (s) for solid, (g) for gas, and (l) for liquid.
To complete and balance the given equation for a gas-evolution reaction, we need to determine the products formed when HNO3(aq) reacts with Li2S and ensure that the equation is balanced.
First, let's identify the ions present in each compound:
HNO3(aq) contains the ions H+ and NO3-.
Li2S contains the ions Li+ and S2-.
An important thing to note is that gas-evolution reactions typically involve the release of H2, CO2, or another gas. In this case, we need to determine if any of the ions mentioned can form a gas.
Since H+ cannot form a gas on its own, we can turn our attention to the S2- ion in Li2S. Sulfur (S) can react with acid to produce a gas called hydrogen sulfide (H2S). Therefore, HNO3(aq) can react with Li2S to produce H2S gas.
Let's write the balanced chemical equation for this reaction:
HNO3(aq) + Li2S → H2S(g) + _____
To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation.
For nitrogen (N), we have one atom on the left side from HNO3 and none on the right side. To balance this, we add a coefficient of 1 before Li2S:
HNO3(aq) + 1 Li2S → H2S(g) + _____
Next, we balance the hydrogen (H) atoms. There are 1 H atom on the left side and 2 H atoms in H2S on the right side. We add a coefficient of 2 before HNO3:
2 HNO3(aq) + 1 Li2S → H2S(g) + _____
Finally, we balance the sulfur (S) atoms. There is 1 S atom in Li2S on the left side and 1 S atom in H2S on the right side. The equation is now balanced:
2 HNO3(aq) + 1 Li2S → H2S(g) + 1 LiNO3(aq)
The final balanced equation for the reaction of HNO3(aq) and Li2S is:
2 HNO3(aq) + Li2S → H2S(g) + LiNO3(aq)
Note: (aq) indicates that the compound is in aqueous solution, and (g) indicates a gas state.