Vocab 6

5. in a closed system, the mass of the system must remain constant over time, even after a reaction
6. a chemical reaction that can be undone
7. a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols
9. A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons
11. a substance that takes part in and undergoes change during a reaction, the starting materials of a reaction
16. in a closed system, the energy of the system must remain constant over time, even after a reaction
18. the breakdown of a single compound into two or more fragments of smaller compounds or individual elements
20. both reactants and products are present in concentrations which have no further tendency to change with time
21. Products are the species (compounds or elements) formed from chemical reactions.
23. a compound that is used as fuel in a combustion reaction, contains hydrogen and carbon, sometimes oxygen
24. chemical reaction in which one element replaces an/other element in a compound.

1. a compound that is used as fuel in a combustion reaction, contains hydrogen and carbon, sometimes oxygen
2. chemical reaction accompanied by the absorption of energy, usually heat or light
3. chemical reaction where two reactant ionic compounds exchange ions to form two new product compounds with the same ions
4. exothermic reaction with a hydrocarbon and oxygen as reactants and carbon dioxide and water as products
8. a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.
10. the speed that a chemical reaction changes reactants into products
12. chemical reaction that releases energy, usually as light or heat
13. a number placed in front of an element of compound formula in a chemical equation to help balance the equation
14. type of reaction in which multiple reactants combine to form a single product
15. the amount if a substance in a given amount of space
17. a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change
19. minimum energy required to get a chemical reaction started
22. a solid product that forms after a chemical reaction of two liquids