Chemistry--Balancing Chemical Equations, Symbols, Reaction Types

A chemical reaction is a chemical ______________.

change

In a chemical reaction the original products are the __________, and the resulting substance is the _____________.

reactants, product

What four things are indicators for a chemical reaction?

1. change in appearance

2. heat and light released

3. odor

4. noise

Melting ice is an example of a ____________ change.

physical

Toasting a marshmallow is an example of a _______________ change.

chemical

Chemical reactions ____________ or ______________ energy.

release, absorb

Most chemical reactions are ________________.

exothermic

Energy comes from ________________.

bond formation

Atoms cannot be ___________________________, all the atoms we start with we must end up with. A balanced equation has the same # of each element on both sides of the equations.

created or destroyed

Never ____________________ to balance an equation.

change a subscript

The arrows separate the ______________ from the ________________.

reactants, products

(s) after the formula=_______________________.

solid

(l) after the formula= ________________________

liquid

(g) after the formula= ________________

gas

(aq) after the formula= ______________________________

dissolved in water, an aqueous solution

A _____________________ is a substance that speeds up a reaction without being changed or used up by the reaction, enzymes are biological or protein catalysts.

catalyst

What are the 4 main types of reactions?

1. combination reactions

2. decomposition reactions

3. single replacement

4. double replacement

What happens in a synthesis (combination) reaction?

two substances combine to make one compound

What happens in a decomposition reaction?

one reactant breaks apart into two or more elements or compounds

What happens in a single replacement reaction?

one element replace another (reactants must be an element and a compound)

In a single replacement, the products will be ___________________________.

a different element and a different compound

What happens in a double replacement reaction?

two things replace each other, positive ions switch places (reactants must be two ionic compounds or acids)

A + B ----> AB

combination

AB -----> A + B

decomposition

A + BC ----> AC + B

single replacement

AB + CD ----> AD + BC

double replacement

combustion reaction

a chemical reaction that occurs when a substance reacts with oxygen(O2), producing CO2 and H2O releasing energy in the form of heat and light

acid-base reaction

a reaction where an acid (HX) reacts with a base(YOH) to produce water(H2O) and a salt(YX)