Predicting entropy change from an equation: an interactive particle model. Pick a balanced equation, then raise the reaction progress to watch reactant particles turn into product particles in a closed container, and see whether the number of gas particles, and so the entropy, rises or falls.

You can call the sign of an entropy change without a single number: just count the gas

Entropy is a measure of how spread out particles and their energy are. Gas particles roam the whole container, so they carry far more entropy than a packed solid or a liquid. Pick a reaction, then raise the reaction progress and watch gas particles appear or vanish.