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Difficulty: MediumChemical Reactions and Compounds

When solid baking soda (sodium bicarbonate, NaHCO3NaHCO_3) is added to vinegar (acetic acid, CH3COOHCH_3COOH), vigorous bubbling occurs as carbon dioxide gas (CO2CO_2), water (H2OH_2O), and sodium acetate (CH3COONaCH_3COONa) are produced. Why is this process classified as a chemical change rather than a physical change?

  1. A
    The solid dissolves and undergoes a reversible state change from solid to gas.
  2. New chemical substances with distinct molecular structures and properties are formed.Answer
  3. C
    Thermal conduction causes the liquid vinegar to boil rapidly into carbon dioxide vapor.
  4. D
    The total mass of the resulting products increases because new atoms are created.

Answer

New chemical substances with distinct molecular structures and properties are formed.
A chemical change is characterized by the rearrangement of atoms and the formation of one or more entirely new substances with distinct physical and chemical properties, as seen with the production of carbon dioxide, water, and sodium acetate.

Step-by-Step Solution

1
Analyze the starting reactants and resulting products in the scenario.
Reactants (NaHCO3NaHCO_3 and CH3COOHCH_3COOH) produce entirely new compounds (CO2CO_2, H2OH_2O, and CH3COONaCH_3COONa).
Identifying the formation of new chemical identities is fundamental to determining the type of change.
2
Distinguish between physical and chemical processes.
Physical changes alter only the form or state of matter without changing chemical formulas, whereas chemical changes involve the rearrangement of atoms into new chemical compounds.
The defining characteristic of a chemical change is the synthesis or decomposition of chemical bonds resulting in new substances.

Key Concept

Chemical change involves breaking and forming chemical bonds to produce new substances with different properties.
Estimated Time:1m 0s
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Topics

Chemical Reactions and Compounds

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