Answer:
1) petroleum, mixture, not found on periodic table
2) hydrogen and helium, mixture, contains "and"
3) iron sulphide, compound, ends with "ide"
4) carbon dioxide, compound, ends with "ide"
5) salt water, mixture, not found on periodic table
6) milk and sugar, mixture, contains "and"
7) silver nitrate, compound, ends with "ate"
8) sodium carbonate, compound, ends with "ate"
9) carbon electrode, mixture, not found on periodic table
10) astatine, element, found on periodic table
11) argon, element, found on periodic table
12) oxidane, compound, contains "ane"
13) iron and sulphur, mixture, contains "and"
14) methane, compound, contains "ane"
Explanation: