1. break up or scatter.   Hint First letter clue   2. calculate or reckon.   First letter clue   3. sear with caustic or hot iron to prevent infection.   First letter clue   4. hide or disguise.   First letter clue   5. move faster or speed up.   First letter clue   6. surround or enclose.   First letter clue   7. eaten into or affected by chemical action.   First letter clue