SCIENCE Lesson 3

high

The activation of some reactions is so ________that more energy is needed to start the reaction.

faster, collide, faster

Chemical reactions occur _____if the particles _______more often or if the particles move ________when they collide.

reactants

Catalysts also do not change the ________or the products of the reaction.

catils, activation

A ________increases reaction rate by lowering the _________energy of a reaction.

change

A catalyst is not itself permanently _______during a chemical reaction.

energy, bonds

All reactions require ________to start the breaking of ________.

enzyme

An __________is a catalyst that speeds up chemical reactions in living cells.

concentration

An increase in ____________also increases reaction rate because there are more particles to _________with each other

collide

At higher temperatures, particles _______more often.

absorbs

Breaking a chemical bond ______energy from the surroundings.

Chemical energy, bonds

Energy released in a chemical reaction comes from ______ _______ that is contained in chemical_____________

pressure, substances

For gases, increased ________pushes particles closer together, and more __________occur.

releases

Forming a chemical bond __________energy to the surroundings.

less, reactants

In these reactions, ______energy is required to break the bonds of the _______than is released when products form.

more, reactants

In these reactions, ____energy is required to break the bonds of the ________than is released when products form.

absorb

Most chemical reactions release more energy than they______

release

Some chemical reactions absorb more energy than they ________

start,

Some chemical reactions do not _______by themselves

inhibitors

Substances called __________slow down or stop a chemical reaction.

exposed

Surface area is the amount of ________outer area of a solid.

low, surroundings

The activation energy of some reaction is so ____that enough energy to start the reaction comes from the ____.

conserved

The energy in chemical bonds and the energy absorbed or released is always __________

speed

The rate of a reaction is the _______at which it occurs.

energy

They also collide with more ______.

Surface area

___________area can affect the rate of a reaction.

Temperature, temperature

__________can affect the rate of reaction because at higher _________particles move faster.

Activation energy

_________is the minimum amount of energy that is needed to start a chemical reaction.

Exothermic

_________reactions are chemical reactions that release thermal energy.

Increased, particles, particles

_________surface area increases the rate of reaction because more _________on the surface of a solid come in contact with the ________of another substance.

Endothermic

reactions are chemical reactions that absorb thermal energy.