"Balancing Chemical Equations - Abdullah Naeem": HTML5 Crossword

Across

5. A type of chemical reaction in which a single substance is broken down into two or more products (13)
7. A measure of the amount of matter in an object (4)
9. A chemical reaction that requires heat (11,8)
10. The new substances that form from the chemical change (8)
11. The most basic and small unit of structure and life which is the building blocks of the universe (5)
12. A shorter form of a substance (6)
13. Shows us substances involved in a chemical reaction (8,8)
16. A number that gets placed in front of a chemical formula (11)
17. A type of reaction in which two compounds exchange elements or molecules with one another (6,11)
18. A number underneath an element in a chemical equation that describes how many atoms of each element are in there (9)
19. The arrow that shows the reactants turning into products (5)

Down

1. When a chemical reaction occurs, the mass of the product should be equal to the mass of the reactants (3,2,12,2,4)
2. A pure substance that is made of one type of atom (7)
3. Anything that has mass and takes up space (6)
4. The substances that undergo chemical changes (9)
6. A type of chemical reaction in which two or more reactants form a single product (9)
8. A type of reaction in which an element reacts with a compound to form a new compound and a different element (6,11)
14. A group of atoms (9)
15. A Balanced equation occurs when the number of atoms involved in the reactants side is _______ to the number of atoms in the products side (5)