Chem 115 Exam 1 Review

Question 1

2. Identify an element

Answer 1

Atoms with the name number of protons in their nucleus belong to the same element.

Question 2

2. Identify a compound

Answer 2

a pure substance composed of two or more elements that are chemically bonded in fixed proportion

Question 3

2. Identify a mixture?

Answer 3

matter that has a constant composition and cannot be broken down to simpler matter by any physical process.

Question 4

Define pure substance

Answer 4

matter that has a constant composition and cannot be broken down to simpler matter by any physical process.

Question 5

Define homogeneous

Answer 5

a mixture in which the components are distributed uniformly and the composition and appearance are uniform.

Question 6

Define heterogeneous

Answer 6

a mixture in which the components are not distributed uniformly, so that the mixture contains regions of different compositions.

Question 7

Proper units of density

Answer 7

g/cm3 or kg/L

Question 8

Define Accuracy

Answer 8

how close a measured value is to the actual value of a give phenomenon

Question 9

Define Precision

Answer 9

reproductibility in measurement sometimes reflected in the number of sig figs in a measurement

Question 10

What did J.J Thomson contribute to atomic structure

Answer 10

Discovery of the electron and its mass. 9.11X10-19 g

Question 11

What did Robert Millikan contribute to atomic structure

Answer 11

charge of an electron it’s negative
1.602 x10-19 C

Question 12

Describe Rutherford’s gold foil experiment and identify the important
conclusions drawn from it?

Answer 12

Is about a source of aphla particles being positive chard being pointed at a gold foil surround by a photographic plate that will most particles straight through but a small number will deflect.

Question 13

Define wavelength

Answer 13

a repeating disturbance that perpetuates through some medium

Question 14

Define frequency

Answer 14

the number of crests of a wave that pass a stationary point of reference per second.

Question 15

Define electromagnetic radiation

Answer 15

waves that move at the speed of light.

Question 16

Explain how light acts like both a wave and a particle?

Answer 16

Wave- particle Duality

Question 17

Describe the photoelectric effect and how it was important in our understanding of the nature of light?

Question 18

Relate the energy of electromagnetic radiation to its frequency and/or wavelength?

Question 19

Describe what a photon is?

Question 20

Explain what the sign on the energy of a photon (+ or -) tells you about an electronic transition in an atom?

Question 21

Describe the Bohr model of the atom, and how it gives rise to line spectra?

Question 22

Relate why quantum mechanics was necessary to describe atoms?

Question 23

Identify the four quantum numbers of the wavefunction Y and show
how they are related to one another?

Question 24

Explain what an atomic orbital is (in terms of the Schrodinger
wavefunction)?

Question 25

Use the rules of quantum numbers (and Pauli and Hund’s Rule) to build
electron configurations for multi-electron atoms (using spdf notation)?