1. machine to separate substances by spinning.   centrifuge   eccentricity   fauna   congruence   Hint Half-n-half Clue   2. opening or gap.   converse   emollient   equinox   aperture   Half-n-half Clue   3. maker of maps.   antiseptic   cartographer   discrepancy   anemia   Half-n-half Clue   4. floating sheet of ice.   floe   arboretum   decomposition   dissertation   Half-n-half Clue   5. ointment that helps in soothing pain.   friction   awl   balm   component   Half-n-half Clue   6. attrition by rubbing or disagreement.   analogy   contagion   friction   assumption   Half-n-half Clue   7. agent to speed up chemical reaction without it changing.   aureole   converse   catalyst   cipher   Half-n-half Clue