science exam Flashcards

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1
Q

What is step one in a stars life cycle?

A

NEBULA
- Stars start in a cloud of dust called a nebula
- Nebulae are multiple light years across and can spawn multiple star systems.
- Dust and gas move together under gravity and begin to spin as a disk.

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2
Q

what is step 2 in a stars life cycle?

A

PROTOSTAR
- a ball of mass starts to form in the centre of the disk from step 1
- when the mass gets larger and larger, the ball gets hotter and starts to glow forming a protostar
- The temperature continues to rise and eventually gets hot enough for nuclear fusion to begin.

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3
Q

What is step 3 in a stars life cycle?

A

MAIN SEQUENCE
- The star will fuse Hydrogen in a more-or-less stable fashion.
- Bigger stars tend to use their fuel faster (because of the pressure)
- A star can be in the main sequence anywhere between 20 million to 80 billion years.

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4
Q

what is step 4 in a stars life cycle?

A

RED SUPERGIANT OR RED GIANT
- Stars eventually use up all their Hydrogen and do one of 3 things depending on their mass

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5
Q

what happens to high mass stars during step 4?

A

The highest mass stars will begin to fuse Helium and expand into a Red Supergiant star.

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6
Q

what happens to medium mass stars during step 4?

A

The medium mass stars also fuse Helium and expand, but only to the size of a Red Giant (the size of a large star)

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7
Q

what happens to low mass stars during step 4?

A

The lowest mass stars will skip this step entirely (fusing Helium) and collapse into a white dwarf.

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8
Q

what do red giants and red supergiants do throughout their lifetime?

A

Red Giants and Red Supergiants expand about 500x their original size.

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9
Q

what is step 5 in a stars life cycle?

A

SUPERNOVA OR WHITE DWARF
Once the Helium is used up (from high or medium mass stars), a star will do one of 2 things:
1: The star will collapse, but re-gain enough pressure in its core to fuse heavier elements. the result of this pressure is a supernova.
2: The star will collapse and be unable to fuse anything else. It will slowly cool and radiate heat as a White Dwarf until it becomes a Brown Dwarf (cold).

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10
Q

What is step 6 in a stars life cycle?

A

NEUTRON STAR OR BLACK HOLE
If a star goes supernova, it will do one of 2 things depending on their mass:
1: The core will become a ball of mass so dense it becomes a neutron star.
2: The core will become a ball of mass that is even more dense that it becomes a black hole.

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11
Q

how does a star become a supernova in its life cycle?

A

once the helium is used up, the high or medium mass star will collapse, but re-gain enough pressure in its core to fuse heavier elements. the result of this pressure is a supernova.

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12
Q

how does a star become a brown dwarf?

A

once the helium is used up, the high or medium mass star will collapse and be unable to fuse anything else. It will slowly cool and radiate heat as a White Dwarf until it becomes a Brown Dwarf (cold).

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13
Q

what is star class m?

A

Temp: 2,500 - 3,500
Colour: red

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14
Q

What are the star classes g and f?

A

temp: 5000 - 7500
colour: yellow

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15
Q

What is star class k?

A

temp: 3500-5000
colour: orange

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16
Q

what is the star class a?

A

Temp: 7500 - 10,000
Colour: white

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17
Q

What are the star classes o and b?

A

Temp: 10,000 - 50,000
Colour: blue

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18
Q

what is the order of star classes from coldest to hottest?

A

M
K
G, F
A
B, O

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19
Q

what are the two variables that control a stars formation?

A

Mass and temperature

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20
Q

what are the forces that control and stars formation?

A

gravity and pressure

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21
Q

what is the big bang theory?

A
  • The entire universe formed from a single dense point which suddenly expanded.
  • The universe, and time itself, began 13.9 billion years ago and all the matter and energy in the universe came from the Big Bang.
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22
Q

who came up with the big bang theory?

A

Edwin Hubble

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23
Q

what was Hubble’s evidence for the big bang theory?

A

1: Hubble studied the light spectrum of each galaxy and calculated
a) The speed the galaxy was moving away from our Milky Way Galaxy and
b) The distance of the galaxy from our own galaxy
2: He discovered a relationship between these two measurements:
The farther away a galaxy was from our own, the faster it was moving away.
This shows that the universe is expanding.

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24
Q

what is the particle theory?

A

All Matter is made up of tiny particles that have empty spaces between them.

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25
Q

what are the spacing, forces and motion in a solid property?

A

very close together in a pattern
strong attraction
particles vibrate in a fixed position

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26
Q

what are the spacing, forces and motion in a gas property?

A

flying around very far apart
very weak attraction between particles
move at high speed and only sometimes collide with each other

27
Q

what are the spacing, forces and motion in a liquid property?

A

somewhat close together in groups
weaker attraction between particles
particles move around and slide past each other (flow)

28
Q

what does the physical state of a substance depend on?

A

The Physical State of a substance depends on temperature and pressure

29
Q

what is a change of state?

A

A Change of State (e.g. solid to liquid) is a Physical Change

30
Q

what is a chemical change?

A

A Chemical Change is when a new substance is created.
A Chemical Change creates a new substance that has different physical & chemical properties & a new chemical formula.
Chemical changes are not usually reversible. The substance cannot be changed into what it was before.
Chemical changes are the result of chemical reactions.

31
Q

what is a physical change of state?

A

Physical Changes of State involve the “gain” or “loss” of Heat Energy
Alters only the form or state of a substance (freezing, breaking, melting).
No new substance is created.
The chemical composition remains the same.
It is usually reversible.

32
Q

classification of matter

A

Matter
into pure substance or mixture
pure substance into elements or compounds
mixture into homogenous or heterogenous mixtures

33
Q

Example of a heterogenous mixture and homogenous mixture and what are they?

A

homogenous: solutions (juice)
heterogenous: mixture (salad)

34
Q

what are qualitative properties?

A

A property that can be observed or described without detailed measurement, using your senses.

35
Q

what are the parts of an atom and what are they called?

A

protons(+) neutrons(+-) and elections(-)
called subatomic particles

36
Q

what are quantitative properties?

A

A property that can be measured or assigned a particular value.

37
Q

5 examples of qualitative properties?

A

Colour
Odour
State
Texture
Lustre
Malleability

38
Q

5 examples of quantitative properties?

A

Viscosity
Melting point
Boiling point
Solubility
Hardness
Conductivity
Density

39
Q

what is a physical property?

A

a characteristic or description of a substance that may help to identify it.
Some physical properties can be observed by using your senses.
Others are observed using simple tests and measurements.

40
Q

what is a chemical property?

A

A chemical property is a characteristic of matter that can only be observed when one substance changes into a different substance, such as iron into rust or wood into ashes

41
Q

what equation gives you the number of neutrons?

A

atomic mass - protons
= neutrons

42
Q

what are electrons equal to?

A

protons and electrons = the same

43
Q

what does a lightyear mean?

A

The distance travelled by light in one year (ly)

44
Q

what is an astronomical unit?

A

The Astronomical unit equals the average distance between the Sun and Earth

45
Q

light second?

A

300,000km the distance light travels in a second

46
Q

closest planet to sol? farthest?

A

Mercury closest
neptune farthest

47
Q

order of planets

A

mercury
venus
earth
mars
jupiter
saturn
uranus
neptune

48
Q

how many planets?

A

8

49
Q

what is the carbon cycle

A

breathing plants animals and fossil fuels

50
Q

how do humans effects the carbon cycle

A

burning fossil fuels

51
Q

what are ionic compounds reactions between?

A

Ionic Compounds are Reactions between ONLY Metals and Non-Metals.

52
Q

properties of ionic compounds:
Shape:
Changes of State:
Hardness:
Electrically Conductive:
Conductive to Heat:

A

Shape: Ions form crystals.
Changes of State: Ions have high melting points and high boiling points.
Hardness: They’re hard and brittle.
Electrically Conductive: They conduct electricity when they are dissolved in water.
Conductive to Heat: They’re good insulators

53
Q

what does a voltmeter and ammeter have to be in?

A

voltmeter parallel

54
Q

chemical properties

A

combustibility
reactivity
solubility

55
Q

how to calculate there and back

A

divide by two

56
Q

malleability

A

the ability to be easily changed into a new shape

57
Q

covalent compound

A

a pair of electrons is shared between two non-metal elements
SHARING OF ELECTRONS

58
Q

ionic compounds

A

Transfer of electrons

59
Q

diatomic

A

HOBrFINCl

60
Q

covalent compounds prefixes

A

name first element
add ide to the end of the second
at the number of each element
(di, mono, tri, tetra)
if one atom in the first element no need for mono

61
Q

how to determine resistance?

A

voltage/current

62
Q

what does voltage in series do?

A

ADD

63
Q

what are the trophic levels?

A

Producer (autotroph)
- Plants
Primary consumer
- Tend to be Herbivores
Secondary consumer
- Tend to be Omnivores
Tertiary consumer
- Tend to be Carnivores

64
Q

density

A

density = mass/ volume