Science Chapter 5 Vocab Flashcards
Chemical change
A change in which one or more substances combine or break apart to form new substances.
Physical Change
A change that alters the form or appearance of a material but does not make the material into another substance.
Reactants
A substance that enters into a chemical reaction.
Products
A substance formed as a result of a chemical reaction.
Precipitate
A solid that forms from a solution during a chemical reaction.
Exothermic reaction
A reaction that releases energy, usually in the form of heat.
Endothermic reaction
A reaction that absorbs energy.
Chemical equation
A short, easy way to show a chemical reaction, using symbols.
Law of conservation of mass
The principle that the total amount of matter is neither created nor destroyed during any chemical or physical change.
Open system
A system in which matter can enter from or escape to the surroundings.
Closed system
A system in which no matter is allowed to enter or leave.
Coefficient
A number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction.
Synthesis
A chemical reaction in which two or more simple substances combine to form a new, more complex substance.
Decomposition
A chemical reaction that breaks down compounds into simpler products.
Replacement
A reaction in which one element replaces another in a compound or when two elements in different compounds trade places.
Activation energy
The minimum amount of energy needed to start a chemical reaction.
Concentration
The amount of one material in a certain volume of another material.
Catalyst
A material that increases the rate of a reaction by lowering the activation energy.
Enzymes
A biological catalyst that lowers the activation energy of reactions in cells
Inhibitor
A material that decreases the rate of a reaction.
