Both Fourier's law of heat conduction and Fick's law of mass diffusion can be expressed

as

$Q^{}=-kA(\frac{dT}{dx}).$

What do the quantities $Q^{},k,A,$ and $T$ represent in

$($a$)$ Heat conduction and

$($b$)$ Mass diffusion?

Fick's law of diffusion is expressed on the mass and mole basis as

$m_{\text{d}\text{i}\text{f}\text{f},A}^{}=-A{D}_{AB}(\frac{d{w}_A}{dx})$ and

$N_{\text{d}\text{i}\text{f}\text{f},A}^{}=-CA{D}_{AB}(\frac{d{y}_A}{dx}),$ respectively.

Are the diffusion coefficients $D_{AB}$ in the two relations the same or different?