# Why is unit conversions in chemistry category and not in some other subject? like converting mm to cm.These are not a part of chemistry though.......

For units of volume we use $1 \cdot L$, $1000 \cdot m L$, $1000 \cdot c {m}^{3}$, $1 \cdot {\mathrm{dm}}^{3}$, AND ALL of these are the same volume. Chemistry sometimes uses non standard units of length, i.e. $1 \cdot \text{Angstrom}$ $\equiv$ $1 \times {10}^{-} 10 \cdot m$, and this is a HIGHLY useful unit - all structural chemists would think in terms of $\text{angstroms}$.