chapter 7- chemical reactions

reactant

the ________- the substance that undergo a chemical change

product

the _______- the new substance that was formed

chemical equation

a chemical __________ is a representation of a chemical reaction in which the reactants and products are expressed as formulas

coefficients

the big numbers in front of the formula

reaction

when a substance undergoes a chemical change, a chemical _______ is occurring

mass

during a chemical reaction, the ______ of the reactants always equals the mass of the product

conservation of mass

the law of _______ __of__ ______ states that mass is neither created nor destroyed in a reaction

atoms

in order to demonstrate this, the number of _______ of each element on the left side of the arrow must equal the number of atoms on the right side

coefficient

you can balance the number of atoms by changing the _______ only

subscript and formula

you cannot change the _____ __and__ _______

decomposition reaction

a ________ _______ is when on compound breaks down into 2 or more products

synthesis reaction

a _____ _______ is a reaction in which 2 or more reactants form one product

double-replacement reaction

a ________-________ _____ is one in which 2 different compounds exchange ions and form 2 new compounds

combustion reaction

a ______ ________ is one in which a substance reacts rapidly with oxygen, often producing heat and light

number and type

just as we classify matter into different types, we can also classify reactions by different types based on the _____ __and__ _________ of reactants and products

one

a synthesis reaction is a reaction in which 2 or more reactants form ______ product

synthesis

decomposition is the opposite of ________

single

a _______- replacement reaction is a reaction in which a single element takes the place of another element in a compound

hydrocarbon and O2

in a combustion, the reacts are always a _____ __and__ ____

chemical energy

_______ _______ is the energy stored in the chemical bonds of a substance

exothermic reaction

if energy releases, this is an _____ ______

endothermic reaction

if energy is absorbed by the surroundings is an ___ ______

describe the energy changes that take place during a chemical reaction

during a chemical reaction, energy is either released or absorbed

matter cannot be created or destroyed

explain how energy is conserved during a chemical reaction

energy

the heat that is produced by a gas grill is a form of _______ released by the combination between propane and oxygen-- which produces carbon dioxide, water (in vapor form), and heat

bonds & formation

chemical reactions involve the breaking of chemical ____ __in the reactants and the__ ______ of new and different chemical bonds in the product

diagram

a reaction energy ______ shows the energy change between the reactants and products

endothermic

if the reactants energy is lower than the products, then that means the reaction absorbed energy, so this is an _____ reaction

released

if the reactants energy is higher than the products, then that means the reaction _______ energy, so this is an exothermic reaction

conservation

this principle is the law of _______ of energy

reaction rate

a ______ _____ is the rate at which reactions change into products over time

describe the factors affecting chemical reaction rates

temperature, surface area, concentration, stirring

collide

the reaction rate depends on how often and frequently the particles ________

increase

an increase in temperature will _______ the reaction rate

decrease

a decrease in temperature will ________ the reaction rate

collision

increasing the temperature increases the ________ frequency

higher

the smaller the particle size of a given mass, the _______ it’s surface area, so the more likely it is to react

increase

an increase in surface area increase the exposure of reactants to one another--which ______ the reaction rate

concentration

changing the _______ of the reactants changes the reaction rate

volume

you can change the concentration by changing the ______

amount

you can change the concentration by changing the ______ of the reactant