Multiple Choice
Which of the following substances is attracted to a magnet due to its chemical properties?
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1. Intro to General Chemistry
Chemical Properties
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Which of the following examples shows that a chemical reaction has occurred?
A
Iron rusts when exposed to air, forming Fe2O3.
B
Salt dissolves in water.
C
Ice melts to form liquid water.
D
Water boils and turns into steam.
Verified step by step guidance1
Understand the definition of a chemical reaction: it involves the formation of new substances with different chemical properties from the original substances.
Analyze each example to determine if new substances are formed or if the process is just a physical change (change in state or form without changing chemical identity).
For 'Salt dissolves in water,' recognize that salt (NaCl) dissociates into ions but does not form a new substance; this is a physical change.
For 'Ice melts to form liquid water' and 'Water boils and turns into steam,' note that these are changes in physical state (solid to liquid, liquid to gas) without changing the chemical composition of H2O.
For 'Iron rusts when exposed to air, forming Fe2O3,' identify that iron reacts chemically with oxygen to form a new compound (iron oxide), indicating a chemical reaction has occurred.
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