Witch of these is a mixture? a. calcium b. carbon dioxide c. salt water d. potassium

Salutations!

Salt water is a mixture because salt and water can be separated. A mixture is composed of 2 substances that can be separated. The rest of them are elements.

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)