Ch.3 Atomic and Mol. Structure

Question 1

4 points of the atomic theory:

Answer 1

1. All matter is composed of atoms. Atoms are indivisible and indestructible
2. Atoms of a specific element are identical in mass and properties
3. Compounds are formed by whole number ratios of two or more atoms
4. A chemical reaction is a rearrangement of atoms

Question 2

How do you determine bond length between C-H given bond lengths of C-C and H-H?

Answer 2

1/2 the bond length of C-C + 1/2 the bond length of H-H

Question 3

What is the formula for dH bond energies?

Answer 3

energy bonds broken - energy bonds formed

Question 4

Bonds breaking is an input of energy or release of energy?

Answer 4

input of energy

+ve energy value

Question 5

Bonds forming is an input of energy or release of energy?

Answer 5

energy is released (-ve value)

Question 6

What are two types of molecular orbitals?

Answer 6

• bonding orbitals

- antibonding orbitals

Question 7

What is a bonding orbital?

Answer 7

signs of atomic orbital are the same

Question 8

What are anti-bonding orbitals?

Answer 8

signs of atomic orbitals are different

Question 9

Sigma bond vs pi bond type of overlap of orbitals?

Answer 9

head to head overlap = sigma bond

parallel overlap = pi bond

Question 10

What is the difference between precision and accuracy?

Answer 10

precision = consistency - values are close together
accuracy = experimental value (literature value)