Unit 7 - Chemical Reactions Test

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  • 1/25 Questions

    A(n) _____ chemical equation has the same number of atoms of each element on both sides of the equation.

    • Simple
    • Balanced
    • Unbalanced
    • Complex
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Unit 7 - Chemical Reactions Test - Quiz
About This Quiz

In this scientific quiz, we’ll be putting you up against a gauntlet of questions regarding chemical reactions – the process of transformation from one set of chemical substances to another. Think you have the right brain chemistry for the task?

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  • 2. 

    The breaking down of a substance into two or more substances is ______.

    • Displacement

    • Synthesis

    • Decomposition

    • Endothermic

    Correct Answer
    A. Decomposition
    Explanation
    The breaking down of a substance into two or more substances is referred to as decomposition. This process involves the separation of a compound into its individual elements or simpler compounds. It is the opposite of synthesis, which involves the combination of substances to form a more complex compound. Displacement refers to the replacement of one element by another in a compound, and endothermic describes a reaction that absorbs heat from its surroundings.

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  • 3. 

    According to the law of conservation of mass, if two atoms of hydrogen are used as a reactant, how many atoms of hydrogen must be part of the product?

    • 2

    • 0

    • 1

    • 4

    Correct Answer
    A. 2
    Explanation
    According to the law of conservation of mass, the total mass of the reactants must be equal to the total mass of the products in a chemical reaction. Since two atoms of hydrogen are used as a reactant, in order to conserve mass, there must also be two atoms of hydrogen as part of the product.

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  • 4. 

    Each substance on the left side of the arrow in a chemical equation is a ______.

    • Reactant

    • Product

    • Coefficient

    • Catalyst

    Correct Answer
    A. Reactant
    Explanation
    In a chemical equation, the substances on the left side of the arrow are called reactants. Reactants are the starting materials that undergo a chemical reaction to form new substances, known as products, which are located on the right side of the arrow. Coefficients are used to balance the equation and indicate the relative amounts of each substance involved in the reaction. Catalysts, on the other hand, are substances that increase the rate of a chemical reaction without being consumed in the process.

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  • 5. 
    Study the following equation and choose the term that correctly describes the part identified. The right side of the equation: - ProProfs

    Study the following equation and choose the term that correctly describes the part identified. The right side of the equation:

    • Coefficient

    • Reactants

    • Products

    • Subscript

    Correct Answer
    A. Products
    Explanation
    The term "products" correctly describes the part identified on the right side of the equation. In a chemical equation, the reactants are on the left side and the products are on the right side. The products are the substances that are formed as a result of the chemical reaction.

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  • 6. 

    Each substance to the right of the arrow in a chemical equation is a _____.

    • Catalyst

    • Precipitate

    • Reactant

    • Product

    Correct Answer
    A. Product
    Explanation
    In a chemical equation, the substances to the right of the arrow represent the products. These are the new substances that are formed as a result of the chemical reaction. Therefore, the correct answer is "product".

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  • 7. 

    A substance that speeds up a chemical reaction without undergoing a permanent change itself is a(n) _____.

    • Inhibitor

    • Coeffient

    • Reactant

    • Catalyst

    Correct Answer
    A. Catalyst
    Explanation
    A catalyst is a substance that speeds up a chemical reaction without undergoing a permanent change itself. It works by providing an alternative pathway with lower activation energy for the reaction to occur. This allows the reaction to proceed at a faster rate, but the catalyst remains unchanged and can be used again in subsequent reactions. In contrast, an inhibitor slows down or prevents a chemical reaction, a coefficient is a number that appears in front of a chemical formula to balance the equation, and a reactant is a substance that participates in a chemical reaction.

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  • 8. 

    A chemical reaction in which two or more substances combine to form another substance is a _____ reaction.

    • Synthesis

    • Decomposition

    • Reactant

    • Product

    Correct Answer
    A. Synthesis
    Explanation
    A chemical reaction in which two or more substances combine to form another substance is known as a synthesis reaction. In this type of reaction, the reactants come together to create a new product. This process involves the formation of chemical bonds between the reactants, resulting in the creation of a more complex substance. Synthesis reactions are commonly observed in various chemical processes, such as the formation of water from hydrogen and oxygen molecules.

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  • 9. 
    Study the following equation and choose the term that correctly describes the part identified. The left side of the equation: - ProProfs

    Study the following equation and choose the term that correctly describes the part identified. The left side of the equation:

    • Coefficient

    • Reactants

    • Products

    • Subscript

    Correct Answer
    A. Reactants
    Explanation
    The left side of an equation represents the reactants, which are the substances that undergo a chemical reaction to form new products. In a chemical equation, the reactants are typically written on the left side of the arrow, indicating that they are the starting materials for the reaction. The reactants are the substances that are consumed or used up during the reaction.

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  • 10. 

    When one element replaces another element in a compound, the reaction is a ____ reaction.

    • Synthesis

    • Single-displacement

    • Decomposition

    • Double-displacement

    Correct Answer
    A. Single-displacement
    Explanation
    When one element replaces another element in a compound, the reaction is a single-displacement reaction. In this type of reaction, a more reactive element displaces a less reactive element in a compound, resulting in the formation of a new compound and a free element. This reaction is also known as a substitution reaction, where one element is substituted for another in a compound.

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  • 11. 

    Accoriding to the law of conservation of mass, how does the mass of the products in a chemical reaction compare with the mass of the reactants?

    • The mass of the products is greater.

    • The mass of the reactants is greater.

    • There is no relationship.

    • The masses are equal.

    Correct Answer
    A. The masses are equal.
    Explanation
    According to the law of conservation of mass, the total mass of the reactants in a chemical reaction is always equal to the total mass of the products. This means that no mass is gained or lost during a chemical reaction. The atoms in the reactants rearrange to form new products, but the total number of atoms and their mass remains the same. Therefore, the correct answer is that the masses are equal.

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  • 12. 
    Balance the following equation: - ProProfs

    Balance the following equation:

    • 3, 1, 3, 1

    • 3, 3, 2, 3

    • 3, 2, 3, 1

    • 1, 2, 1, 2

    Correct Answer
    A. 3, 1, 3, 1
  • 13. 

    Substances that prevent certain chemical reactions are called _____.

    • Endothermics

    • Catalyst

    • Inhibitors

    • Products

    Correct Answer
    A. Inhibitors
    Explanation
    Substances that prevent certain chemical reactions are called inhibitors. Inhibitors work by slowing down or stopping the reaction by interfering with the active sites of enzymes or by blocking the formation of the transition state in a chemical reaction. They are commonly used in industries to control the rate of reactions or to prevent unwanted reactions from occurring.

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  • 14. 
    Study the following equation and choose the term that correctly describes the part identified. The big 2 in “2H2O” is a: - ProProfs

    Study the following equation and choose the term that correctly describes the part identified. The big 2 in “2H2O” is a:

    • Coefficient

    • Reactants

    • Products

    • Subscript

    Correct Answer
    A. Coefficient
    Explanation
    The big 2 in "2H2O" is a coefficient. In chemical equations, coefficients are used to balance the number of atoms on both sides of the equation. In this case, the coefficient 2 indicates that there are two molecules of water (H2O) involved in the reaction.

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  • 15. 

    If energy in the form of heat is required for a chemical reaction to take place, the reaction is ______.

    • Exothermic

    • Reactant

    • Balanced

    • Endothermic

    Correct Answer
    A. Endothermic
    Explanation
    If a chemical reaction requires energy in the form of heat to occur, it is considered endothermic. In an endothermic reaction, heat is absorbed from the surroundings, causing a decrease in temperature. This type of reaction is characterized by the breaking of bonds within the reactants, which requires energy input. As a result, the products have more energy than the reactants, and the reaction is not spontaneous.

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  • 16. 
    Study the following equation and choose the term that correctly describes the part identified. The small 2 in “2H2O” is a: - ProProfs

    Study the following equation and choose the term that correctly describes the part identified. The small 2 in “2H2O” is a:

    • Coefficient

    • Reactants

    • Products

    • Subscript

    Correct Answer
    A. Subscript
    Explanation
    The small 2 in "2H2O" is a subscript. In chemical equations, subscripts are used to indicate the number of atoms or molecules of each element in a compound. In this case, the subscript 2 indicates that there are two molecules of water (H2O) present.

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  • 17. 

    A chemical reaction in which the energy released is primarily in the form of heat is ____.

    • Flammable

    • Exothermic

    • Endothermic

    • Endergonic

    Correct Answer
    A. Exothermic
    Explanation
    An exothermic reaction is a chemical reaction that releases energy, primarily in the form of heat. This means that the products of the reaction have less energy than the reactants, resulting in the release of heat. This is opposite to an endothermic reaction, where energy is absorbed from the surroundings. Flammable refers to the ability of a substance to catch fire, while endergonic refers to a reaction that requires energy input. Therefore, the correct answer is exothermic.

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  • 18. 
    What type of reaction is shown in the chemical equation NH3 + HCl  NH4Cl? - ProProfs

    What type of reaction is shown in the chemical equation NH3 + HCl  NH4Cl?

    • Synthesis

    • Decomposition

    • Single-displacement

    • Double-displacement

    Correct Answer
    A. Synthesis
    Explanation
    The chemical equation NH3 + HCl → NH4Cl represents a synthesis reaction. In a synthesis reaction, two or more reactants combine to form a single product. In this case, ammonia (NH3) and hydrochloric acid (HCl) react to form ammonium chloride (NH4Cl).

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  • 19. 

    What is an insoluble solid that forms as the result of a double-displacement reaction called?

    • A precipitate

    • An inhibitor

    • A coefficient

    • A catalyst

    Correct Answer
    A. A precipitate
    Explanation
    In a double-displacement reaction, two compounds react to form two new compounds, one of which is often an insoluble solid called a precipitate. This solid forms when the cations and anions in the reactants switch partners, resulting in the formation of a new compound that is not soluble in the solvent. Therefore, the correct answer is "a precipitate."

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  • 20. 

    Which of the following could represent a single-displacement reaction?

    • Element + element = compound

    • Compound = element + element

    • Element + compound = element + compound

    • Compound + compound = compound + compound

    Correct Answer
    A. Element + compound = element + compound
    Explanation
    A single-displacement reaction occurs when one element replaces another element in a compound. In the given answer, "element + compound = element + compound," an element is reacting with a compound and replacing one of the elements in the compound. Therefore, this equation represents a single-displacement reaction.

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  • 21. 
    What type of chemical reaction is shown in the equation 2H2O 2H2 + O2? - ProProfs

    What type of chemical reaction is shown in the equation 2H2O 2H2 + O2?

    • Synthesis

    • Decomposition

    • Single-displacement

    • Double-displacement

    Correct Answer
    A. Decomposition
    Explanation
    The given equation shows a decomposition reaction. In this type of reaction, a compound breaks down into two or more simpler substances. In the equation, 2H2O (water) decomposes into 2H2 (hydrogen gas) and O2 (oxygen gas).

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  • 22. 

    What information is useful for predicting whether metal will replace another metal in a compound?

    • A coefficient

    • A subscript

    • An activity series

    • Atomic mass values

    Correct Answer
    A. An activity series
    Explanation
    An activity series is useful for predicting whether a metal will replace another metal in a compound. This is because an activity series ranks metals based on their reactivity, with the most reactive metals at the top and the least reactive metals at the bottom. By comparing the position of two metals in the activity series, it can be determined whether a metal will replace another metal in a compound based on their relative reactivity.

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  • 23. 

    An example of a balanced chemical equation is _______.

    • AgNO3 + NaCl   4AgCl + 2NaNO3

      Unit 7 - Chemical Reactions Test - Quiz

    • 2AgNO3 + 2NaCl   3AgCl + 2NaNO3

      Unit 7 - Chemical Reactions Test - Quiz

    • AgNO3 + NaCl AgCl + NaNO3

      Unit 7 - Chemical Reactions Test - Quiz

    • AgNO3 + 2NaCl + AgCl AgCl + 3NaNO3

      Unit 7 - Chemical Reactions Test - Quiz
    Correct Answer
    A. AgNO3 + NaCl AgCl + NaNO3
    Explanation
    The given balanced chemical equation shows the reaction between AgNO3 (silver nitrate) and NaCl (sodium chloride), resulting in the formation of AgCl (silver chloride) and NaNO3 (sodium nitrate). The equation is balanced because the number of atoms of each element is the same on both sides of the equation.

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  • 24. 

    Numbers that precede symbols and formulas in a chemical equation are called ____.

    • Subscripts

    • Superscripts

    • Fractions

    • Coeffients

    Correct Answer
    A. Coeffients
    Explanation
    Coefficients are the numbers that precede symbols and formulas in a chemical equation. They represent the relative number of molecules or atoms involved in the reaction. By adjusting the coefficients, we can balance the equation and ensure that the number of atoms of each element is equal on both sides of the equation. Subscripts, on the other hand, are used to indicate the number of atoms of an element within a molecule, while superscripts are used for indicating charges or indicating the number of atoms in a polyatomic ion. Fractions are not typically used as coefficients in chemical equations.

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  • Current Version
  • Mar 22, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Jan 10, 2013
    Quiz Created by
    Haszshe
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