Question

Aqueous solutions of ammonium phosphate and sodium sulfate are mixed. No precipitate forms and no gas is produced.

Short answer

The chemical formulas of ammonium phosphate and sodium sulfate can be written as (NH4)3PO4 and Na2SO4, respectively. The reaction occurring when these two aqueous solutions are mixed can be represented as: (NH4)3PO4 (aq) + Na2SO4 (aq) -> (NH4)3PO4 (aq) + Na2SO4 (aq) According to the solubility rules, both compounds are soluble in water. Because no chemical reaction occurs, no precipitate forms, and no gas is produced.

Step-by-step solution

Write the reactants and products

First, write down the chemical formulas of the given aqueous solutions. Ammonium phosphate is (NH4)3PO4, and sodium sulfate is Na2SO4. Since no reaction occurs, the products will be the same as the reactants: (NH4)3PO4 (aq) + Na2SO4 (aq) -> (NH4)3PO4 (aq) + Na2SO4 (aq)

Verify the solubility rules

To verify that the compounds remain soluble, we have to check the solubility rules, as provided: 1. All compounds containing alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) are soluble. 2. All compounds containing the ammonium ion (NH4⁺) are soluble. 3. All compounds containing nitrate (NO3⁻), acetate (C2H3O2⁻), or perchlorate (ClO4⁻) ions are soluble. 4. All chlorides (Cl⁻), bromides (Br⁻), and iodides (I⁻) are soluble, except those of silver (Ag⁺), lead (Pb²⁺), and mercury (Hg²⁺). 5. All sulfates (SO4²⁻) are soluble, except those of barium (Ba²⁺), strontium (Sr²⁺), lead (Pb²⁺), calcium (Ca²⁺), and mercury (Hg²⁺). The latter three have limited solubility. 6. Carbonates (CO3²⁻), phosphates (PO4³⁻), sulfites (SO3²⁻), and sulfides (S²⁻) are generally insoluble, except those of alkali metals and ammonium ion. According to the solubility rules: - (NH4)3PO4 has ammonium ion (NH4⁺) which is soluble (rule 2). - Na2SO4 has sodium ion (Na⁺) which is soluble (rule 1). Since both compounds meet the solubility rules, no precipitate will form or gas will be produced when the solutions are mixed, confirming the given information in the problem statement.

Key concepts

Aqueous Solutions

An aqueous solution is a mixture where the solvent is water. It is the most common setting for a chemical reaction in nature and in laboratory environments. Examples include saltwater, sugar water, and various chemical reagents dissolved in water. Water's polarity makes it an excellent solvent for ionic substances and small polar molecules. In aqueous solutions, compounds can react to form new substances, stay dissolved without reacting, or sometimes precipitate out, depending on their solubility.

In the context of the exercise, ammonium phosphate and sodium sulfate are dissolved in water to form aqueous solutions. Since both are soluble in water according to solubility rules, they stay dissolved and no reaction takes place. Understanding the properties of substances in aqueous solutions, like electrolytes - substances that conduct electricity when dissolved, is crucial for many fields, including chemistry, biology, and environmental science.

Chemical Reactions

At the heart of chemistry lies the study of chemical reactions, processes that involve the transformation of substances through breaking and forming chemical bonds. Reactions can result in the formation of new products, release or absorb energy, and include different types like synthesis, decomposition, single replacement, and double replacement reactions.

In our exercise, the mixing of ammonium phosphate and sodium sulfate might suggest a chemical reaction could occur. However, after checking the solubility rules, we confirm that there is no reaction. This is an important reminder that not all mixtures of chemicals result in reactions. It's the understanding of how different substances interact that allows chemists to predict whether a reaction will occur, and if so, what products will form.

Precipitation Reactions

Precipitation reactions are a type of chemical reaction where two aqueous solutions combine to form a solid precipitate. This occurs when the product of a reaction is insoluble in water. These reactions are incredibly important for various fields such as medicine, waste treatment, and geochemical processing.

The absence of a precipitate in our exercise is significant. Initially, it may be assumed that when two ionic compounds in aqueous solution are mixed, a precipitate might form. However, in this case, both ammonium phosphate and sodium sulfate remain dissolved based on their solubility rules. Understanding precipitation reactions can help in predicting whether or not a solid will form in a given chemical reaction.

Solubility Rules

Solubility rules are guidelines for predicting the solubility of compounds in water. These rules are central to understanding reaction outcomes in aqueous solutions. For instance, they tell us that all nitrates are soluble, and most sulfates are soluble, except for those of barium, strontium, and lead.

The exercise demonstrates the application of these rules when two compounds are expected to react. By following the solubility rules, we correctly predict that both compounds in either aqueous solution are soluble and therefore do not react to form a precipitate. For students, mastering solubility rules is imperative for predicting the outcomes of reactions in chemistry, which includes understanding when a precipitate will form in the solution.