Review For Review For MidtermMidterm

•Turn in Reference Pages.Turn in Reference Pages.•Homework 1 through 14 should be Homework 1 through 14 should be complete and turned in. complete and turned in. •All labs should be turned in.All labs should be turned in.•FOR Second Quarter: You will keep all of FOR Second Quarter: You will keep all of your work in a notebook. I will collect the your work in a notebook. I will collect the notebook once every two or three weeks notebook once every two or three weeks and check in all homework at that time. We and check in all homework at that time. We will still have frequent quizzes.will still have frequent quizzes.•Tuesday: Nov 16 Meet at the Write Zone, Tuesday: Nov 16 Meet at the Write Zone, bring your list of references.bring your list of references.

What is Chemistry?What is Chemistry?• A physical science• The study of matter, energy and its

changes.

What are the Branches of What are the Branches of Chemistry?Chemistry?

• Organic Chemistry: Study of carbon-based molecules

• Inorganic Chemistry: Study of the rest of the elements

• Analytical Chemistry: Identification of compounds.

• Physical Chemistry: Study of the relationships of energy and matter.

• Biochemistry: Study of biological molecules such as sugars, starches, enzymes, proteins, fats, DNA and RNA.

List the postulates of Dalton’s List the postulates of Dalton’s Atomic Theory.Atomic Theory.

• Elements are made of tiny particles called atoms.

• All atoms of a given element are identical.• All atoms of a given element are different

from the atoms of other elements.• Atoms can combine with each other(in

small whole number ratios) to form different compounds. (ex: CO, CO2)

• Atoms are indivisible.

Convert from cal Convert from cal Joules Joules1. 5.05 cal

2. 0.101 cal

3. 110 cal

5.05 cal

0.101 cal

110 cal

4.184 J1 cal

4.184 J1 cal

4.184 J1 cal

=21.1J

=0.422J

=460J

What is the Law of What is the Law of Conservation of Energy?Conservation of Energy?

Whatever energy you begin with,

Since none is created or destroyed,

equals the amount of energy at the end.

Whose experiment first proved Whose experiment first proved that atoms were that atoms were divisibledivisible??

• JJ Thomson

Who found the charge to massratio of electrons?

Millikan

Convert from Joules Convert from Joules cal cal1. 3.10 J

2. 0.66 J

3. 150 J

3.10 J

0.66 J

150 J

1 cal4.184 J

1 cal4.184 J

1 cal4.184 J

=0.741 cal

=0.16 cal

=36 cal

Convert the followingConvert the following• 2.3 mg = ____g• 10.5 g = _____kg• 1980 m = ____km• 0.005kL = ___L• 2.1 m = _____cm• 900 cm = ____km

• 2.3 mg = 0.0023 g• 10.5 g = 0.0105 kg• 1980 m = 1.98 km• 0.005kL = 5 L• 2.1 m = 210 cm• 90 cm = 0.009 km

Fill in the ChartFill in the Chart

Isotope Atomic #

# protons or e-

# neutron

Mass number

tin-119

Boron-10

Oxygen-18

Oxygen-17

Fill in the Chart.Fill in the Chart.Isotope Atomic

numberNumber of protons or e-

Number of neutrons

Mass number

Tin-119 50 50 69 119

Boron-10 5 5 5 10

Oxygen-18

8 8 10 18

Oxygen-17

8 8 9 17

What is inertia?What is inertia?• Inertia is the “tendency of an object”

to continue doing the same thing.– A moving object will continue to move

unless a force is applied.– An object at rest will continue to stay at

rest unless a force is applied.• The quantity of inertia an object has,

depends upon its mass. Therefore, heavier objects have more inertia than light objects.

What discovery led to the change from What discovery led to the change from all atoms of the same element are all atoms of the same element are identical, to all atoms of the same identical, to all atoms of the same element are chemically identical?element are chemically identical?

• The discovery of isotopes.

What is the Law of What is the Law of Conservation of MassConservation of Mass

Whatever amount of mass you begin with,

none is destroyed or created, so

that is the same amount of mass you end with.

12 + 32= 44 g

How are matter and energy How are matter and energy different?different?

• Matter is “stuff”. It takes up space, has mass, has inertia.

• Energy is “the ability to do work”. It cannot be observed directly, but the effect on other things can be observed.

What are isotopes?What are isotopes?• Atoms of the same element with

different numbers of neutrons.• They have different masses, but the

same chemical properties.

Which of Dalton’s postulates Which of Dalton’s postulates had to be changed?had to be changed?

• All atoms of a given element are identical.

• Atoms are indivisible.

What is a modelWhat is a model• In our isotopes of Pennium lab, the

pennies were a model for isotopes of elements. Pennies minted after 1982 were made with zinc inside. Pennies minted before 1982 are pure copper. Copper pennies are denser than copper/zinc pennies, but both are worth $0.01.

• Models provide a way to test hypotheses on a smaller scale.

Convert from Cal Convert from Cal Joules Joules1. 0.305 Cal

2. 0.0505 Cal

3. 13 Cal

4.184 J1 cal

4.184 J1 cal

4.184 J1 cal

=12800J

=211 J

=54000J

1000cal1 Cal

1000cal1 Cal

1000cal1 Cal

How was Chemistry How was Chemistry Developed?Developed?

• Scientists develop hypotheses about how the world works.

• Scientists develop experiments to confirm or deny these hypotheses.

What do we study in What do we study in Chemistry?Chemistry?

• We study what happens when things are mixed.

• We study what happens if the environment is changed (heating or cooling, adding substances, increasing or decreasing surface area).

• We make systematic observations of how things affect each other.