Chemical Reactions Notesheet Name: ______

Applied Chemistry

Date:______Period: ______

A.Mechanics of a Chemical Reactions

  1. Chemical Reaction – The type of reaction in which the properties of the ______are different from the ______.
  1. Chemical Change – A change that produces new substances with new ______and ______.
  • Physical changes do ______change the ______of a substance.
  • Nuclear changes involve changes to the ______. Ex) fission and fusion

3. Signs that a chemical change or reaction has occurred:

a)

b)

c)

d)

e)

  1. Chemical Equation – a description of a chemical reaction using ______instead of ______.
  1. Parts of a Chemical Equation

CH4 + O2  H2O + CO2

reactantsproducts

  1. Reactants
  • Written on the ______side of the arrow
  • ______material in a chemical reaction
  1. Products
  • Written on the ______side of the arrow
  • Newly formed substances that are ______in a chemical reaction
  • Properties are ______than those of the reactants.
  1. Arrow
  • ______sign
  • Means ______
  • Separates the ______from the ______.
  1. Plus sign
  • Used to ______reactants and to ______products.

H2 (g) + O2 (g)  H2O (l)

KI(aq) + PbNO3(aq)  PbI2(s) + KNO3(aq)

  1. The following symbols indicate the substance’s physical state:
  • g:
  • l:
  • s:
  • aq: (which means dissolved in )

**The physical states are in parentheses beside the reactant or product.**

Example:H2(g) + Cl2(g)  HCl(g)

  1. What is (are) the reactant(s) in the above equation?
  1. What is (are) the products(s) in the above equation?
  1. What is the physical state of all the substances?
  1. Catalysts are sometimes added to reactants to help ______a chemical reaction.
  • Catalysts are ______in a chemical reaction. They are neither reactants nor products.
  • Catalysts are written ______the yield sign.
  1. Law of Conservation of Mass
  • Mass is neither nor in a chemical reaction, it can only ______. Mass of reactants is the as the mass of the products.
  • The number of each type of atom in the reactants must be ______to the number of atoms in the ______.
  • Since the number of atoms is the same, the ______will be the same on both sides of the reaction.
  • Also, the ______of element will be the same on each side.

B.Balancing Equations

Look at the following equation:

H2 (g) + Cl2 (g)  HCl (g)

# of H atoms ______# of H atoms ______

# of Cl atoms ______# of Cl atoms ______

Does this equation have the same number of atoms of each element on both sides of the equation? ______Therefore, it (does ordoes not) follow the Law of Conservation of mass.

  1. The above equation is called a ______equation.
  2. The equation must be ______with ______(the number in front of a formula for a substance).

H2(g) + Cl2(g) → 2HCl(g)

# of H atoms ______# of H atoms ______

# of Cl atoms ______# of Cl atoms ______

A coefficient of 1(one) is understood and is not necessary in the balanced chemical equation.

Steps for balancing equations:

  1. Write the chemical formula for each reactant and product.
  2. Indicate the state of each substance.
  3. Use______ in front of the substance to balance the equation. The number of each ______should be the ______on both sides of the equation.

NOTE: NEVER CHANGE SUBSCRIPTS!!!

Balance the following equations:

  1. _____ H2(g) + _____ Br2(g) _____ HBr(g)
  2. _____ Na(s) + _____ Cl2(g) _____ NaCl(s)
  3. _____ Na(s) + _____ O2(g)_____ Na2O(s)
  4. _____ Zn(s) + _____ HCl(aq)_____ ZnCl2(aq)+ _____ H2(g)
  5. _____ Fe(s) + _____ O2(g) _____ Fe2O3(s)
  6. _____ P4(s) + _____ O2(g) _____ P2O5(s)
  7. _____ Al2O3(s)+ _____ H2(g)_____ Al(s) +_____ H2O(l)
  8. _____ Ca(s) + _____ O2(g) _____ CaO(s)
  9. _____ Cl2(g)+ _____ AlBr3(aq) _____ Br2(l)+_____ AlCl3(aq)
  10. _____ HgO(s)  _____ Hg(l)+_____ O2(g)

C.Types of Chemical Reactions

  1. Synthesis Reactions
  • Two or more reactants produce ______product
  • A.K.A. ______reactions
  • Follows the pattern: A + B  AB

** Only ONE product**

Example: N2(g)+ 3H2(g)  2NH3(g)

____ reactants  ____ product

  1. Combustion Reactions
  • Chemical reaction involving ______in which light and heat are produced.
  • When fuels are burned in the presence of oxygen, ______and ______are often produced.
  • Follows the pattern:BC + A  BA + CA

Example: CH4(g)+ 2O2(g)  CO2(g)+ 2H2O(g)+ heat energy

  1. Decomposition Reactions
  • Opposite of ______reactions
  • Substance breaks down into ______
  • Chemists can cause decomposition, but decomposition can also be ______.
  • Follows the pattern: AB  A + B

** Only ONE reactant**

Example: 2H2O(g)  2H2(g)+ O2(g)

____ reactant  ____ products

  1. Single Displacement (Replacement) Reactions
  • Change in ______
  • One substance will ______, or ______, another element in a compound.
  • Follows the pattern:A + BC  AC + B

**2 reactants (1 element, 1 compound) and 2 products (1 element, 1 compound) **

Example: Zn + H2SO4  ZnSO4+ H2(g)

  1. Double Displacement (Replacement) Reactions
  • Both substances change ______
  • Follows the pattern:AB + CD  AD + CB

**2 reactants (both compounds) and 2 products (both compounds) **

Example: KI(aq) + PbNO3(aq)  PbI2(s) + KNO3(aq)

D.Reactivity of Metals – SINGLE REPLACEMENT REACTIONS

  1. The reactivity of a metal is based on its ability to ______another in a compound.
  1. If a single replacement reaction occurs, the metal that “cuts in” is ______reactive than the one that was removed.
  1. An activity series of metals is a listing that ranks metals according to their ______.

The MOST active metal is at the ______of the list

The LEAST active metal is at the ______of the list.

  1. The activity series is listed below:

lithium

potassium

barium

strontium

calcium

sodium

magnesium

aluminum

manganese

zinc

iron

cadmium

cobalt

nickel

tin

lead

hydrogen

copper

silver

mercury

gold

The most active metal is ______.

The least active metal is ______.

Which is more active, nickel or iron? ______

Al + CuCl2  ______+ ______

Mg + HCl  ______+ ______

Cu + HCl  ______

E.Treatment of Metals

  1. Metals are treated to protect from ______or to make the metals better suited for specific purposes, such as improving ______or making ______.
  2. Types of Metal Treatments
  1. Galvanizing – ______
  2. Painting - ______
  3. Making Alloys – ______
  1. Common Alloys
  1. Bronze – ______
  2. Brass – ______
  3. Steel – ______
  4. Stainless Steel - ______
  5. Pewter – ______
  6. Solder –______

F.Energy Changes in Chemical Reactions

  1. Exothermic Reactions
  • ______heat into the surroundings.
  • Surrounding will get ______.
  • Sometimes need heat to get them started.
  • A noticeable ______in temperature occurs.
  • Example:
  1. Endothermic Reactions
  • ______heat from the surroundings.
  • Surroundings will get ______.
  • Need heat to keep them going.
  • A noticeable ______in temperature occurs.
  • Example: