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Elements, Compounds and Mixtures — CHEMISTRY STD 8 — Question

ICSE BoardEnglish MediumSTD 8CHEMISTRYElements, Compounds and Mixtures3 Marks
Question
Define the term 'compound'. In the compound carbon dioxide $-$ the elements carbon $\&$ oxygen are combined in a fixed ratio. Explain.
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Answer

A compound is a pure substance made up of two or more different elements $[$atoms$]$ combined chemically in a fixed proportion.
$(a)$ Contains $-$ two or more kinds of atoms, e.g. compound $-$ carbon dioxide $\left[\ce{CO_2}\right]$.
$(b)$ Can be broken down $-$ into two or more simpler substances $-$ by chemical means.
$(c)$ Properties of compounds $-$ differ from those of their elements, e.g. $\ce{CO_2}$ contains elements $-$ Carbon
$\ce{[C]}$ is combustible and Oxygen $\ce{[O]}$ is supporter of combustion - but carbon dioxide is non$-$combustible and non$-$supporter of combustion.

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