Complete the crossword, then click on "Check" to check your answer.

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Across: 1. made of one type of atom 3. limestone, sand and sodium carbonate make this 5. where limestone is dug 6. powdered limestone and clay 7. water, sand, cement and crushed rock 9. they hold atoms together 11. reaction where something breaks down when heated is thermal ... 12. pH greater than 7 13. universal indicator goes this colour in calcium hydroxide solution 14. several elements but not chemically joined 15. small particle, several atoms bonded together

Down: 2. contains lots of calcium carbonate 4. dissolve calcium oxide in water to make ............ lime 7. compound which contains carbon and oxygen 8. compound which contains hydrogen and oxygen 10. common name for calcium oxide