Midterm Review

Question 1

What is chemistry

Answer 1

The study of matter and its properties

Question 2

How did chemistry originate

Answer 2

Originated from alchemy

Question 3

What’s the difference between basic and applied research with an example of each?

Answer 3

Basic research is for the sake of increasing knowledge (climate research)

Applied research is to solve a specific problem (solar cell research)

Question 4

Define mass

Answer 4

A measure of the amount of matter in an object

Question 5

Define matter

Answer 5

Anything that has mass and takes up space

Question 6

What are two examples of a physical property

Answer 6

Freezing water into ice.

Tearing paper

Question 7

Give 2 examples of a chemical property

Answer 7

Fire or burning

Rust/oxidation

Question 8

What’s the difference between a homogeneous mixture and a heterogeneous mixture with an example of each

Answer 8

Homogeneous mixture is a solution has a uniform composition (salt water)

Heterogeneous mixture does not have a uniform composition (cereal)

Question 9

How do you go from a gas to a solid

Answer 9

Deposition

Question 10

How do you go from a solid to a gas

Answer 10

Sublimation

Question 11

Why do scientists need to use standard units of measure

Answer 11

So everyone has the same measurements and uses the same numbers

Question 12

What is a base unit

Answer 12

A unit based on something in the real world

Independent of others

Question 13

How many SI base units are there

Answer 13

7

Question 14

What is the meter based on

Answer 14

The distance of light travels in a vacuum

Question 15

What is volume

Answer 15

The space occupied by an object

Question 16

What is the equation for denstiy

Answer 16

Mass/volume

Question 17

Define accuracy

Answer 17

How close measurements are to a target (accepted value)

Question 18

Define precision

Answer 18

How close measurements are to one another

Question 19

Significant figures indicate the ________ of a mearsurement

Answer 19

Precision

Question 20

What did aristotle believe about the nature of matter

Answer 20

All matter was continuous.

Question 21

What is the law of conversation of mass

Answer 21

Mass is neither created nor destroyed during ordinary chemical reactions or physical changes

Question 22

Describe the experiment that JJ Thomson did with a cathode ray tube

Answer 22

He applied a magnetic field to a cathode ray tube and the tube was attracted to the positive charges in the magnetic field, meaning that the cathode rays are streams of negatively charged particles.

Question 23

What did JJ Thomson discover

Answer 23

The Electron

Question 24

What is the mass:mass ratio of an electron to a hydrogen atom

Answer 24

1/1840

Question 25

Describe the experiment Rutherford performed to test the plum pudding model and what were the results?

Answer 25

He measured positively charged alpha particles deflection through a thin gold foil. He observed that some alpha particles deflected at large angles or bounced straight back. This means that the positive alpha particles were repelled by another positively charged thing.

Question 26

Define atomic number

Answer 26

The number of protons (and electrons) in each atom of an element

Question 27

Define mass number

Answer 27

Total number of protons and neutrons that make up the nucleus of an atom

Question 28

What is a half-life of a radioactive isotope

Answer 28

The time it takes for half of an isotopes radioactive atoms to decay

Question 29

What is the relationship between wavelength and frequency

Answer 29

Inverse. as frequency increases wavelength decreases

Question 30

What is the speed of light approximately

Answer 30

3.00×10⁸ m/s

Question 31

How do you separate white light or sunlight into the individual colors

Answer 31

Pass it through a prism

Question 32

Define quantum

Answer 32

The minimum amount of energy gained or lost by an atom

Question 33

What is the photoelectric effect

Answer 33

Photoelectrons are emitted from a metal's surface when light of a certain frequency (or higher) shines on the surface

Question 34

What did albert einstein propose about the dual nature of light in 1905

Answer 34

Light behaves as both a wave and a particle

Question 35

In Bohrs model of the atom, what happens when an electron moves from excited state down to a ground state?

Answer 35

Light is emitted

Question 36

What is the major limitation of Bohr's model of the atom?

Answer 36

It explains hydrogen's spectrum but fails to explain any other elements spectrum

Question 37

Define Heisenberg's Uncertainty principle

Answer 37

It is impossible to know the precise velocity and position of an object at the same time.

Question 38

What are valence electrons

Answer 38

The outermost electrons in an atom

Question 39

What did Moseley do to "fix" Mendeleev's table?

Answer 39

He discovered each element has a unique atomic number and arranged the elements in the table according to increasing atomic number.

Question 40

Describe metals in terms of appearance, state at room temperature, and conductivity.

Answer 40

Shiny/have luster when smooth and clean Solid at room temp Good conductors

Question 41

Described non metals and terms of their appearance, state at room temperature, and conductivity

Answer 41

Tend to be gases, otherwise dull and brittle solids Bad conductors

Question 42

What group are the noble gases and how reactive are they

Answer 42

Group 18 Virtually unreactive

Question 43

What shape is the p orbital

Answer 43

Bowtie