Chemistry Unit 2 Lesson

Unit 2: Matter,

Masses and Moles

Chemistry 22-23’

I. Introduction

Chemistry happens everyday

●Reactions, movement, energy transfer, enzymes, etc.

I. Introduction

What is Chemistry?

●The study of atoms and molecules

○Atom - “ A little ball of matter”

○Molecule - “Two or more atoms bonded together”

○Chemical reactions - A change in the way the atoms are
bonded together.

I. Introduction

What is Chemistry?

●The study of atoms and molecules

●Focus on the properties of atoms and molecules and the way
they react to each other

1) Analytical Chemistry

The type of chemicals that are in substances.

●Example: Contaminated water or blood samples from a crime
scene.

2) Synthetic Chemistry

Creating new molecules/chemicals that are not found naturally.

●Example: Nylon is a fiber used in clothing that was designed by
synthetic chemists.

●Other examples include medicines, artificial foods, ceramics,
plastics, etc.

3) Physical Chemistry

Focus on how the natural laws of physics apply to chemical reactions.

Concepts such as motion, force, time, thermodynamics, quantum
chemistry and chemical equilibrium.

●Examples: The amount of energy a reaction gives off, atomic
bomb, etc.

4) Biochemistry

The complex chemistry that takes place inside of living things

●Example: How chocolate is turned into energy

Multiple Choice

An analytical chemist looks at

• Focus on how the natural laws of physics apply to chemical reactions.

• The type of chemicals that are in substances.

• Creating new molecules or chemicals that are not found naturally.

• The complex chemistry that takes place inside of living things

Multiple Choice

A synthetic chemist looks at

• The type of chemicals that are in substances.

• Focus on how the natural laws of physics apply to chemical reactions.

• The complex chemistry that takes place inside of living things

• Creating new molecules and chemicals that are not found naturally.

Multiple Choice

A biochemist looks at

• The type of chemicals that are in substances.

• Focus on how the natural laws of physics apply to chemical reactions.

• The complex chemistry that takes place inside of living things

• Creating new molecules and chemicals that are not found naturally.

Multiple Choice

A Physical chemist looks at

• The type of chemicals that are in substances.

• Focus on how the natural laws of physics apply to chemical reactions.

• The complex chemistry that takes place inside of living things

• Creating new molecules and chemicals that are not found naturally.

Multiple Choice

Chemistry is the study of

• Chemical reactants

• Atoms and molecules

• Biochemicals

• Physical laws

These branches of chemistry overlap

Example: Plant-based food

A synthetic chemist can genetically modify plant-based food. An
analytical chemist can analyze the different types of pure substances
in this food. A physical chemist can determine the amount of energy it
takes to create this plant-based food and a biochemist can determine
how the human body reacts to eating this food.

Monday's Assignment

Come up with an example of how the branches of chemistry overlap
and identify what a chemist would do for each section, what you find
in your research relating to each section and other interesting
information you find.

Each slide needs to include a picture and overall presentation needs to
have a theme.

Table presentations on Tuesday

Exit ticket

Posted in the stream. Fill out to the best of your ability

Atoms

Made up of three subatomic particles: Protons, neutrons and
electrons

The smallest piece of matter

Atoms - Atomic nucleus

Atomic nucleus

●Made of protons and neutrons

●Not visible to the human eye

●Contains essentially all the mass of the atom
○Mass is different than weight (more later
on this)

Atoms - Electron cloud

●Electrons occupy the space surrounding the nucleus of an atom.

●Cloud is large in space compared to the nucleus but almost no
mass

●Can have several orbits

Atoms - Charges

Proton - one positive charge

Electron - one negative charge

Neutrons - no charge

Every atom must have a zero electric charge
overall. Therefore the number of electrons
equals the number of protons.

Atoms

Matter and Mass

Matter

1.

An atom is the most basic form of matter
a.

Matter is everything we can feel, see, taste, smell and
touch

2.

Matter is anything that occupies space and has mass.

Matter and Mass

Matter vs. Weight

1.

Matter resist being moved (inertia) but weight is a force caused
by gravity.

Matter vs. Weight

Example: bowling ball vs a feather. The bowling ball has a greater
mass and weight on Earth. In space, a bowling ball still has a greater
mass but they have the same weight because there is not force of
gravity.

Atomic mass and Atomic weight

1.Atoms have mass
a.

Masses of atoms is measured in amu
(atomic mass units)

i.Each proton and neutron has a mass
of 1 amu

ii.

Electron is 1/2000 of a proton or
neutron mass.

iii.

True atomic mass is always a bit
different than the sum of protons
and neutrons.

Atomic mass and Atomic Weight

What is the atomic mass of an element that has 7 protons, 7
electrons and 7 neutrons?

Atomic mass and Atomic Weight

b) General terminology - Atomic mass and atomic weight are used
interchangeably by chemists

c) If the mass is doubled the number of atoms is also double.

Multiple Choice

Which subatomic particles make up the mass of an atom?

• protons only

• protons and neutrons

• protons, neutrons and electrons

• protons and electrons

Multiple Choice

What is the atomic mass of an atom with 32 protons and 31 neutrons?

• 31

• 32

• 62

• 63

Multiple Choice

How many neutrons are there for an atom with a mass of 20 and 11 protons?

• 9

• 11

• 20

• 31

Multiple Choice

What is the atomic mass of element 5 if it has 6 neutrons?

• 5

• 6

• 11

• 30

Multiple Choice

The atomic mass of K

• 35

• 36

• 38

• 39

Multiple Choice

What is matter made up of?

• Air

• non matter

• Atoms

Multiple Choice

How many Sub Atomic Particles are there in an atom?

• 1

• 2

• 3

Multiple Choice

Identify Name of subatomic particles in an atom.

• Electrons

• Protons

• Neutrons

• All of them

Multiple Choice

What charge is present on Protons?

• Negative

• Neutral

• Positive

• All of them

Multiple Choice

What charge is present on Electrons?

• Negative

• Neutral

• Positive

• All of them

Moles: Counting and weighing atoms

A.

Moles
a.

In general, a mole of atoms weighs
the same in grams as its atomic
mass.
i.Example: Helium has a mass of
4 amu so a mole of helium
weighs 4 grams

b.

A name for a certain amount of
atoms

Moles: Counting and weighing atoms

What is the mass of 1 mole of carbon?

Moles: Counting and weighing atoms

What is the mass of 3 moles of hydrogen?

Moles: Counting and weighing atoms

b. A Mole is a name for a certain amount of atoms

Ex: A dozen of eggs

c. One mole = 602,200,000,000,000,000,000,000

i. 1 mole = 6.022❌

1023 atoms

ii. Size comparison: 1 mole of marbles would be bigger than the
moon. But a mole of most atoms would fit in the palm of
your hand.

Moles: Counting and weighing atoms

1 mole of atoms of carbon is equal to 1 mole
of atoms of gold.

Using moles is important because you can find
the number of atoms in a substance

Equation: # of moles = Weight in grams

Atomic mass in amu

Moles: Counting and weighing atoms

Without the concept and equation of moles it
would be very difficult to tell how much of a
substance you had. Chemistry would not be
possible.

Equation: # of moles =

Weight in grams

Atomic mass in amu

Moles: Counting and weighing atoms

Equations

1 mole = 6.022✖1023

Number of moles =

Mass (g)

Atomic mass or

molar mass

Multiple Choice

Which has more molecules?

• 1 mole H₂O

• 1 mole Al(OH)₃

• 1 mole NaCl

• There are all the same

Multiple Choice

How many moles of carbon atoms are there in 5g of carbon? molar mass of carbon = 12.10 g

• 60 mol

• 17 mol

• 0.42 mol

• 7 mol

Multiple Choice

How many atoms of iodine are in a mole of iodine?

• 53

• 63.55g

• 126.9

• 6.02 x 10²³

Multiple Choice

The mass of one mole of an element is equal to

• its atomic number from the periodic table, but in amus.

• its atomic mass from the periodic table, but in amus.

• its atomic mass from the periodic table, but in grams.

• its atomic number from the periodic table, but in grams.