Astronomy Physics & Chemistry

Question 1

3 forms of energy

Answer 1

1. Kinetic (motion)
2. Radiative (light)
3. Potential (stored energy which may be converted)

Question 2

Mass-energy?

Answer 2

Embodies idea that mass itself is form of energy, which Einstein discovered with E = mc^2

Question 3

Thermal energy?

Answer 3

Represents collective kinetic energy of many individual atoms or molecules moving randomly within substance like rock or the air. Higher temperature = more rapid motion = more thermal energy.

Question 4

Law of conservation of energy?

Answer 4

Energy can change from one form to another but it can’t be created or destroyed.

Question 5

Electromagnetic waves?

Answer 5

Light which is characterized by rapidly changing electric & magnetic fields.

Question 6

Light is characterized by?

Answer 6

Wavelength, the distance between adjacent peaks
Frequency, rate at which electric & magnetic fields change.

Unit of frequency = Hertz = waves or cycles per second.

Question 7

Photons

Answer 7

The distinct pieces in which light comes with.

Question 8

What is the speed of light?

Answer 8

Wavelength of photon x frequency of photon.

Longer wavelength = lower frequency
Shorter wavelength = higher frequency.

Question 9

Electromagnetic spectrum?

Answer 9

Complete range of possibilities of light.

Question 10

Visible light?

Answer 10

Lilght that we can see, which is tiny portion. Goes from 400nm to 700nm (one nanometer is a billionth of a meter).

Question 11

Infrared?

Answer 11

Light with wavelengths longer than those of red light.
Radio waves are longest-wavelength light.

Question 12

Region near border between infrared & radiowaves?

Answer 12

Microwaves.

Question 13

Ultraviolet?

Answer 13

Light with wavelengths shorter than blue light. Shortest wavelength is gamma rays.

Question 14

Region between ultraviolet and gamma rays?

Answer 14

X-rays.

Question 15

Spectroscopy?

Answer 15

Collecting light through telescope then dispersing it into a spectrum in much the same way a prism disperses light into rainbow of color.

Question 16

3 basic types of spectra that we observe?

Answer 16

1. Continuous spectrum - smooth light across broad range of wavelengths
2. Emission line spectrum - bright lines on dark background
3. Absorption line spectrum - dark lines on continuous background.

Question 17

Thermal radiation?

Answer 17

Dense objects which emits light with a continuous spectrum, which allows us to determine the object’s surface temperature.

Question 18

What can spectral lines tell us?

Answer 18

Each chemical element, ion and molecule produces its own unique pattern of spectral lines - this pattern helps us to identify what produced it and can allow us to determine the chemical composition of distant objects. Sometimes we can even determine isotopes.

Question 19

What are atoms build of?

Answer 19

Protons, neutrons & electrons.

Question 20

Where are protons & neutrons found?

Answer 20

Tiny nucleus at center of atom. Rest of atom’s volume contains electrons which surrounds nucleus. Most of atom’s mass resides in its nucleus because protons and neutrons are each about 2000 times as massive as an electron.

Question 21

What do properties of atom mainly depend on?

Answer 21

Electrical charge in its nucleus.

Question 22

How do charges of protons and electrons and neutrons work?

Answer 22

We define the proton as basic unit of positive charge. An eelctron has a negative charge. Neutrons are neutral.

An atom is held together by attraction between positively charged protons in nucleus and negatively charged electrons that surround the nucleus.

Question 23

Ions?

Answer 23

Atoms that lose or gain electrons, which means they have a net electrical charge. Positive ion: atom that has lost one or more electrons, so it has an overall positive charge. Negative ion: atom that has gained one or more electron, giving it a net negative charge.

Question 24

Relationship between charged particles?

Answer 24

Opposite charged attract one another, similarly charged repel.

Most of atoms contain same number of electrons as protons, making them electrically neutral.

Interactions between atoms are almost exclusively interactions between electrons (as nucleus is deeply buried).

Question 25

Atomic number?

Answer 25

Number of protons in a nucleus.

Question 26

Atomic mass number?

Answer 26

Combined number of protons and neutrons in an atom.

Electrons have to be same number as atomic number. Atomic mass number always has same neutrons or more neutrons.

Question 27

Molecules

Answer 27

Combined atoms

Question 28

Compounds

Answer 28

Molecules made up of atoms of two ore more different elements.

Question 29

Organic molecules/organic compounds

Answer 29

Complex chemistry of molecules containing carbon.

Question 30

3 phases of molecules

Answer 30

Gas, liquid & solid.

Question 31

Chemical bond?

Answer 31

Interactions between electrrons that hold the atoms in a molecule together.

Question 32

How can changes in pressure or temperature cause phase changes in molecules?

Answer 32

Higher temperature or pressure causes higher vibrations, which means the molecules are not held as tightly together (which is beneficial for chemical reactions)

Question 33

Vaporization

Answer 33

Process by which molecules break free.

Question 34

Sublimation?

Answer 34

Vaporization from a solid

Question 35

Evaporation?

Answer 35

Vaporization from a liquid.