matter is defined as anything that has

mass:

mass is almost always measured in kilograms but sometimes measured in...

atom:

elements:

what are atoms made of

physical change:

chemical change:

chemical changes occur because of...

color, density, hardness, melting point

these are examples of

chemical bonds

chemical bonds form because of the _______ between charges

a _______ reaction occurs when two or more reactants combine to form a single product.

which one shows reactants

_____ indicates chemical reaction in a chemical equation

Bonds break and reform during chemical reactions. Reactants and products contain the same atoms, but they are ___________ during the reaction, so reactants and products are ___________ substances.

all ________ _______ involve energy

the number of atoms of reactants __ the number of atoms of products

The law of ________________________________________ states that matter_____________________ be created or destroyed in chemical reactions. In every chemical reaction, the ______________________ of matter must end up in the products as started in the reactants. ______________________ chemical equations show that mass is conserved in chemical reactions.

In ______________________ reactions, more energy is released when bonds form in products than is used to break bonds in reactants. These reactions_______________ energy to the environment, often in the form of______________________

In ________________________ reactions, more energy is ___________ to break bonds in reactants than is released when bonds form in products. These reactions __________________ energy from the environment.