Transcript 22. Section 3.3 answers and practice

Today's Outline
Topic: All Naming Practice
Class Outline:
- Textbook assignment 3.3Review
- All Naming Practice
Today’s Assigned Work:
- All Naming Practice(homework)
Upcoming Assignments:
All Naming ICA Tuesday Nov. 8th
Balancing and Types of Rxn ICA Monday Nov. 14th
Chemistry Unit Test Friday Nov. 18th
Quote: “ A mistake repeated more than once is a decision.” –Paulo Coelho
Section 3.3
Assignment
Chemical Equations and the Law of Conservation of Mass
Chemical Reaction
• A process in which pure substances undergo a change, forming a
different pure substance
Reactant
• An element or compound that undergoes a chemical reaction.
Product
• An element or compound that is formed in a chemical reaction.
Coefficient
• A number placed in front of a chemical formula in a balanced
chemical equation to show how many atoms, molecules or ions are
involved.
Chemical Equation
• A representation of a chemical reaction that uses chemical formulas
and symbols.
1. Chemical reactions take place every day without us noticing. Look at
table 3.6 on page 128 and identify the chemical reaction that keeps
you alive and healthy.
• A human performing respiration is an example of a chemical reaction
that keeps you alive and healthy each day.
• Also, the photosynthesis of an oak tree provides us with oxygen that
we need as well.
2. What are the reactants in the chemical reaction you
identified in question #1.
• In human respiration the reactants are oxygen and glucose.
• In photosynthesis the reactants are carbon dioxide and water.
3. What are the products in the chemical reaction you
identified in question #1.
• The products of human respiration are carbon dioxide and water.
• The products of photosynthesis are glucose and oxygen.
4. Excess ammonium containing compounds can cause an overgrowth of
algae in oceans and lakes. How can bacteria be used to remove the
excess ammonium ions from the water?
• Bacteria can convert harmful ammonium ions (ammonium nitrite)
that are dissolved in water and convert them into gaseous nitrogen
and liquid water.
• In areas where excess ammonium has caused an overgrowth of algae,
bacteria can be used to clean up the water.
5. Identify the chemical equation that describes the process
bacteria are using to breakdown the ammonium ions.
• Bacteria use the following process to break down ammonium ions:
Ammonium nitrite → nitrogen + water
NH4NO2 → N2 + 2H2O
6. Explain how Lavoisier discovered the law of
conservation of mass.
• Antoine Lavoisier made a very important contribution to
science when he recognized that the mass of the
reactants in a chemical change were equal to the mass of
the products.
• He performed many experiments using a closed system,
carefully measuring the mass of reactants and products.
He worked with mercury (l) oxide which reacts to form
mercury and oxygen when heated.
• His results were always the same; the total mass of the
products were equal to the total mass of the reactants.
7. State the law of conservation of mass.
• The law of conservation of mass states that in a chemical reaction,
the total mass of the products is always the same as the total mass
of the reactants.
• In other words, what goes in must come out!
8. State the atomic theory.
• The atomic theory states that each atom in the
reactants is also present in the products.
• It is important to remember that atoms are neither
created nor destroyed in a chemical reaction so the
mass does not change.
• In other the words, the same number of atoms of
each element that entered a chemical reaction
must also exit.
9. What is included in a chemical equation?
• Chemical equations show the formulas for the elements and compounds
involved:
NH4NO2 → N2 + 2H2O
• Word equations use the names of the elements and compounds:
Ammonium nitrite reacts to form nitrogen gas and water.
10. Why is a skeleton equation considered incomplete?
Include an example in your answer.
• Skeleton equations are considered incomplete because they do not
reflect the law of conservation of mass. They do not include the
number of atoms of each element on both sides of the equation.
NH4NO2 → N2 + H2O
11. What is a balanced chemical equation? Include an
example in your answer.
• A balanced chemical equation reflects the law of conservation of
mass.
• In a balanced chemical equation the same number of atoms of each
element are represented on both sides of the chemical equation.
NH4NO2 → N2 + 2H2O
12. What are the four states of substances that a chemical equation
may also provide?
• Chemical equations may also provide information about the states of
the reactants and products.
• Solid (s)
• Liquid (l)
• Gas (g)
• Aqueous (aq) – dissolved in water
All Naming Review
• Ionic Compounds:
• Binary
• Multivalent
• Polyatomic
• Molecular
Writing a Formula: Binary Ionic Compounds:
Write the correct formula for the compounds
containing the following ions:
1. Na+, S22. Al3+, Cl-
3. Mg2+, N3-
Naming Binary Ionic Compounds
 Examples:
NaCl
ZnI2
Al2O3
Transition Metals
Elements that can have more than one possible charge
MUST have a Roman Numeral to indicate the charge on
the individual ion.
1+ or 2+
2+ or 3+
Cu+, Cu2+
Fe2+, Fe3+
copper(I) ion iron(II) ion
copper (II) ion iron(III) ion
Examples of Older Names of Cations formed
from Transition Metals
(you do not have to memorize these)
Transition Metals Naming
Complete the names of the following binary compounds with variable
metal ions:
FeBr2
CuCl
SnO2
Fe2O3
Naming Polyatomic Compounds
Contains at least 3 elements
There MUST be at least one polyatomic ion
(it helps to circle the ions)
Examples:
NaNO3
Sodium nitrate
K2SO4
Potassium sulfate
Al(HCO3)3 Aluminum bicarbonate
or
Aluminum hydrogen carbonate
Learning Check
1. aluminum nitrate
2. copper(II) nitrate
3. Iron (III) hydroxide
4. Tin(IV) hydroxide
Learning Check
1.
Na2CO3
2 . Ca(HCO3)2
Naming Molecular Compounds
CO2 Carbon dioxide
CH4 methane
BCl3
boron trichloride
All are
formed from
two or more
nonmetals.
Ionic
compounds
generally
involve a metal
and nonmetal
(NaCl)
Molecular (Covalent) Nomenclature
for two nonmetals
• Prefix System (binary compounds)
1.
Less electronegative atom
comes first.
2.
Add prefixes to indicate # of atoms. Omit mono- prefix on the FIRST
element. Mono- is OPTIONAL on the SECOND element (in this class, it’s
NOT optional!).
3.
Change the ending of the
second element to -ide.
Molecular Nomenclature Prefixes
PREFIX
monoditritetrapentahexaheptaoctanonadeca-
NUMBER
1
2
3
4
5
6
7
8
9
10
Molecular Nomenclature: Examples
• CCl4
• N 2O
• SF6
More Molecular Examples
• arsenic trichloride
• dinitrogen pentoxide
• tetraphosphorus decoxide
Mixed Practice Worksheet
•Make sure you figure out if it is ionic or
molecular before you start naming.
Today's Outline
Topic: All Naming Practice
Class Outline:
- Textbook assignment 3.3Review
- All Naming Practice
Today’s Assigned Work:
- All Naming Practice(homework)
Upcoming Assignments:
All Naming ICA Tuesday Nov. 8th
Balancing and Types of Rxn ICA Monday Nov. 14th
Chemistry Unit Test Friday Nov. 18th
Quote: “ A mistake repeated more than once is a decision.” –Paulo Coelho