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What is a precipitate?

A. A gas formed during a chemical reaction

B. A liquid formed when two aqueous solutions react

C. A solid formed when two aqueous solutions react

D. A solution formed during a chemical reaction

Answer Explanation:

A) A gas formed during a chemical reaction: While gases can indeed be produced during chemical reactions, a precipitate specifically refers to a solid that forms during a reaction.

B) A liquid formed when two aqueous solutions react: Precipitates are not liquids. They are solids that are formed when certain ions combine to form an insoluble compound.

C) A solid formed when two aqueous solutions react (Correct Answer): A precipitate is indeed a solid substance that forms when two aqueous solutions react and certain ions combine to create an insoluble compound.

D) A solution formed during a chemical reaction: A precipitate is not a solution. It is the solid product that separates out of a solution during a chemical reaction due to its limited solubility.

Therefore, the Correct Answer is C.

More Questions on TEAS 7 Science

  • Q #1: What is an appropriate pH value for hydrochloric acid?

    A. pH 2-4

    B. pH 1-3

    C. pH 0-2

    D. pH 3-5

    Answer Explanation

    Rationale for each choice:

    A) pH 2-4: While hydrochloric acid is indeed highly acidic, a pH range of 2-4 would suggest a slightly less concentrated solution. However, this range might still be appropriate for dilute or partially neutralized hydrochloric acid.

    A) pH 1-3 (Correct Answer): Hydrochloric acid typically has a very low pH due to its strong acidic nature. A pH range of 1-3 is commonly observed for concentrated hydrochloric acid solutions.

    C) pH 0-2: This range suggests an even stronger acidity, which could be true for very concentrated hydrochloric acid solutions, although they might not commonly occur in typical laboratory or industrial settings.

    D) pH 3-5: This pH range would indicate a significantly less acidic solution compared to hydrochloric acid. Such a pH range might be more appropriate for weak acids or diluted hydrochloric acid solutions rather than the concentrated form.

  • Q #2: When acids and bases react together, we call this a:

    A. Neutralization reaction.

    B. Decomposition reaction.

    C. Synthesis reaction.

    D. Redox reaction.

    Answer Explanation

    A. Neutralization reaction. (Correct Answer): When acids and bases react, they undergo a neutralization reaction, resulting in the formation of water and a salt. In this reaction, the acidic properties of the acid are neutralized by the basic properties of the base.

    B. Decomposition reaction: A decomposition reaction involves the breakdown of a compound into smaller substances. It does not typically describe the reaction between acids and bases.

    C. Synthesis reaction: A synthesis reaction involves the formation of a compound from simpler substances. It does not typically describe the reaction between acids and bases.

    D. Redox reaction: A redox reaction involves the transfer of electrons between reactants. While redox reactions can occur in certain acid-base reactions, they are not specific to the reaction between acids and bases. The typical reaction between acids and bases involves proton transfer rather than electron transfer. Therefore, "neutralization reaction" is a more specific and accurate term for this type of reaction.

  • Q #3: What is produced when an acid reacts with ammonia?

    A. Water

    B. Ammonia and Water

    C. Ammonium salt

    D. Hydrogen gas

    Answer Explanation

    A) Water: Water is not typically produced when an acid reacts with ammonia. Water may be present in the reaction mixture, but it is not a direct product of the reaction between the acid and ammonia.

    B) Ammonium chloride: Water and ammonia  are not typically produced when an acid reacts with ammonia. 

    C) Ammonium salt (Correct Answer): When an acid reacts with ammonia, an ammonium salt is typically formed. The specific ammonium salt produced depends on the acid used in the reaction.

    D) Hydrogen gas: Hydrogen gas is not typically produced when an acid reacts with ammonia. The reaction between an acid and ammonia does not involve the liberation of hydrogen gas.