MIDTERM INFO

MIDTERM INFO• The Midterm is comprehensive

– County Assessment (1st & 2nd Quarter)• 50 MC Questions & 1 BCR

– Teacher-Designed Exam (1st & 2nd Quarter)• 25 MC Questions

MidTerm Exam Schedule

Tues, 1/15 Full Day –Period 4B Exam during the regular time pd

Wed, 1/16 Day 2 -Examinations – Periods 1 & 2 Schools close 3 hours early.

Thurs, 1/17 Day 3 -Examinations – Periods 3 & 4A Schools close 3 hours early.

Fri, 1/18 Day 4 -Examinations – Periods 5 & 6 Schools close 3 hours early.

Chemistry Midterm Chemistry Midterm ReviewReview

Chemistry Midterm Chemistry Midterm ReviewReview

Day #2Day #2

Agenda• Practice Problems and Review

Sheet

Homework• Review Sheet # 2 – due Monday

or Tuesday

Practice Problem• Difference between an organic

and inorganic cpd is…

• Organic cpds have a C - H bond. Inorganic cpds can have C or H but not this bond.

Review• Show accuracy and precision using

a dart board.

Accuracy vs. Precision• Accuracy – closeness to the actual

value

• Precision – reproducibility

Review• What is the Law of Conservation of

Mass and Energy?

• Mass and energy are neither created nor destroyed during ordinary chemical reactions or physical changes.

• They are just rearranged!• The mass of all the reactants is equal

to the mass of all the products.• The energy that goes in to the reaction

is equal to the energy that comes out.

Answer

Review• Draw Bohr’s Model for Argon

Review• Where on the periodic table do we

find the s, p, d, and f blocks?

Practice Problem• Write the formulas for the

following: (a) barium carbonate, (b) sodium phosphate, and (c) carbon tetrachloride

Answers• a) BaCO3

b) Na3PO4

c) CCl4

Review Question• Name the following compound:

• Cu(BrO3)2

Answer• Copper(II) bromate

Review• List the symbol, charge, and

penetration power for each type of radiation:– Alpha particles– Beta particles– Gamma radiation

NameName SymbolSymbol ChargeCharge MassMass

(amu)(amu)

PenetrationPenetration

Power Power

AlphaAlpha +2+2 44 4.0 cm air 4.0 cm air 0.005 cm 0.005 cm

tissue tissue no no

penetration penetration through leadthrough lead

BetaBeta - 1- 1 0.000550.00055 6-300 cm air 6-300 cm air 0.006-0.5 cm 0.006-0.5 cm

tissuetissue.0005-0.03 .0005-0.03

cm leadcm lead

GammaGamma 00 00 400 m air400 m air

500 cm 500 cm tissuetissue

3 cm lead3 cm leadhttp://www.avon-chemistry.com/nuclear_24.gif

Alpha Radiation α

238 4 U ? + He

92 2Uranium-238 Alpha Particle

Note that the mass number always decreases by 4 after the alpha emission.

Atomic number decreases by 2

Alpha Radiation α

238 234 4 U Th + He

92 90 2Uranium-238 Thorium-234 Alpha Particle

Beta Radiation β 234 0 Th + e 90 -1

Thorium-234 Beta particle

By combining the charges from the bottom of the two symbols, figure out the symbol for the remaining particle

?

Beta Radiation β

234 234 0 Th Pa + e 90 91 -1Thorium-234 Beta particle

During the emission, a Thorium neutron becomes a proton and an electron. The electron is emitted as a beta particle.

Pa

Protactinium-234

Practice Problem• Give 2 examples of quantitative

data. Give 2 examples of qualitative data.

AnswersQuantitative data = how big, how

fast, how tall = measuredQualitative = relates to our 5 senses

– color, texture, odor, shape

Practice ProblemA small sphere has a mass of 2.5 grams. It has a density of 2.9 g/cm3. Determine the volume of the sphere.

Answer• 0.86 cm3

Review• How can we tell individual element

apart using a spectrometer?

Elements Emit only Specific Wavelengths

•Individual elements emit a spectrum containing discrete lines

•This is called a line spectrum

Review

Label each substance as a chemical change, physical change, chemical property, or physical property:

a. densityb. melting an ice cubec. reacts with oxygend. penny turns greene. dissolving sugarf. Colorg. Grilling a hamburger

Review

Label each substance as a chemical change, physical change, chemical property, or physical property:

a. density – physical propertyb. melting an ice cube – physical changec. reacts with oxygen – chemical propertyd. penny turns green – chemical changee. dissolving sugar – physical changef. Color – physical propertyg. Grilling a hamburger – chemical change

Review• Classify each of the following as:

elements (E), compounds (C),homogeneous mixtures (Hom), or heterogeneous mixtures (Het).

1.Copper 3. Lemonade2.Carbon dioxide 4. SaladThink of two other examples of each.

Answer

1.Copper - E2.Carbon dioxide - C3.Lemonade – Hom4.4. Salad – Het

Review• If electrons in an atom have the lowest

possible energy, the atom is in a state.

• If the electron absorbs energy from an outside source (heat, electrical current), the atom is in an state.

• How does this pertain to a flame test?

Answer• If electrons in an atom have the lowest

possible energy, the atom is in a ground state. • If the electron absorbs energy from an

outside source (heat, electrical current), the atom is in an excited state.

Review

• Identify the shape of each of the following molecules:

• (a) ammonia (NH3)

• (b) water (H2O)

Answer• (a) Pyramidal

• (b) Bent

Review• List radiation of the

electromagnetic (EM) spectrum from shortest to longest wavelength.

Answer

Gamma, x-rays, UV, visible light, IR, Microwave, radioVisible light = VIBGYOR