Agenda: 2/19• Warm-up: Origin of the Elements

•

• Review of Radioactive Isotopes • Half Life Calculations • Fission and Fusion

• Mole Practice

Review: Isotopes• What does the “235” in Uranium-235 mean?

• What is another way to represent the isotope Uranium -235?

• How do Carbon-12 and Carbon-14 differ?

Review: Radioactive IsotopesA radioactive isotope has an __________nucleus that

undergoes _____________ changes. - Emits particles

- 1.- 2.

- Emits energy in the form of __________ waves. - Transmutates (changes) into another element

Fill in the missing symbols & identify the type of particle emitted

Answers

• Write a balanced nuclear equation for each decay process indicated.

• a. The isotope Th-234 decays by an alpha emission. • • • • b. The isotope Fe-59 decays by a beta emission

Answers

Half life Calculations• How much of a 100g sample of an unstable isotope

remains after 25 years if the half life is 5 years?• Determine how many “half life intervals”. • Calculate the amount of original sample remaining after

each ½ life• Simplify the calculations

• 100g

Half Life Problems• How much of a 60g sample of an unstable isotope

remains after 2 days if the half life is 12 hours?

7.5 g

Half Life Problems• How much of a 20 g sample of an unstable isotope

remains after 3 sec if the half life is 0.5 seconds?

Nuclear Fission – Example: Catawba Nuclear Energy Plant – Lake Wylie

For Student notes:

Nuclear FusionExample: Sun’s (Star’s) Energy

ORIGINS OF ELEMENTReading Analysis:

Teachers' Domain: The Origin of the Elements

Teachers' Domain: The Elements: Forged in Stars

• Moles: a counting unit in chemistry• Mole calculation review & practice• Molar Mass of Compounds

Mole Flow Chart

Mole

MassGas volume

Atoms Compounds

Practice problems: Moles and Mass

• What is the mass of 0.5 moles of S?

• How many grams is equivalent to 0.137 moles of Fe?

• 4.63 mol P = ? grams P

Practice problems

• How many moles are in 84.3 grams of Si?

• 50 grams of Ne = ? moles of Ne

Mole and Atom Conversions• How many atoms of Al are in 2.5 moles?

• How many atoms of Ag are in 0.26 moles?

• How many atoms of He are in 0.0023 moles?

Moles and Volume (Gases only)• How many Liters of He are in 0.023 moles?

• How many moles are in 60 L of Neon?

Molar Mass of Compounds• NaOH H₃PO₄

• H₂O PCl₃

• MgCl₂ H₂SO₄

Mole Conversion of Compounds• How many grams are in 5 moles of CO₂?

• How many atoms are in 5 moles of CO₂?

• How many liters are in 5 moles of CO₂?