chemistry

2. The basic unit of a chemical element.
4. A pleasant-smelling colorless volatile liquid that is highly flammable.
6. A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
7. A chemical bond in which two pairs of electrons are shared between two atoms.
8. A stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.
10. A colorless, transparent, odorless, tasteless liquid that forms the seas, lakes, rivers, and rain and is the basis of the fluids of living organisms.
12. Below 0°C.
14. Ascertain the amount of a constituent in (a solution) by measuring the volume of a known concentration of reagent required to complete a reaction with it, typically using an indicator.
15. A substance that has no fixed shape and yields easily to external pressure; a gas or (especially) a liquid.

1. An electromagnetic wave of high energy and very short wavelength, which is able to pass through many materials opaque to light.
3. A solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivity
5. Great chemist
6. A colorless, volatile, sweet-smelling liquid that makes people sleep
9. The action of bringing a liquid to the temperature at which it bubbles and turns to vapour
11. A compound that, when dissolved in water, gives a pH of less than 7.0 or a compound that donates a hydrogen ion
13. An airlike fluid substance which expands freely to fill any space available, irrespective of its quantity.