Chemistry

2. / The centre of an atom that contains protons and neutrons
5. / Compound that dissolves in water
6. / H20
9. / Measures heat
11. of a reaction/ products are formed during chemical reactions as reagents are consumed
13. / Element of an atom
14. / A chemical process where two substances interact to form a new substance
15. of conservation of mass / that the atoms of an object cannot be created or destroyed but can be moved around and be changed into different particles.
16. Reaction / When two substances react
19. / The negatively charged part of an atom
20. / An expression in which symbols and formulae represent a chemical reaction

1. / particles that fill their container though have no definite shape or volume
3. / A substance made up of one kind of atom; it cannot be broken down
4. / Energy in the form of waves
7. / Absorbing heat
8. / A new substance produced by a chemical reaction
10. / Giving off heat
12. / A substance that reacts with another
17. / The smallest unit of an element
18. / A substance made up of two or more elements chemically combined