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8th Grade > Science Midterm > Flashcards

Science Midterm Flashcards

1
Q

matter

A

anything that has mass and takes up space.

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2
Q

mass

A

amount of matter in an object

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3
Q

What is the unit of mass

A

grams (g)

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4
Q

weight

A

a measure of the gravitational forces on an object

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5
Q

Can an objects weight change on the location of the object?

A

yes

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6
Q

Does the mass of an object change based on its location?

A

no

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7
Q

What instrument would be used to measure mass?

A

triple-beam balance

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8
Q

What is the standard scientific unit for weight?

How else can it be represented?

A

standard- Newton (N)

also represented as pounds (lbs)

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9
Q

What is the formula for volume?

A

V=lwh (length x width x height

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10
Q

In what units is volume expressed?

A

Liters (L) or mL

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11
Q

How is volume measured (what instruments)?

A

Graduated Cylinders or beakers

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12
Q

What method can be used to determined the volume of an object?

A

Water displacement.

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13
Q

Density

A

measure of the amount of mass in a given volume

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14
Q

How does the density of an object change with the amount of the object that there?

A

It does not change.

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15
Q

What is the formula for Density?

A

D=m/v

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16
Q

physical property

A

a characteristic of a substance that can be observed and measured without changing the identity of the substance

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17
Q

solubility

A

ability of a substance to dissolve in another substance

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18
Q

Examples of common physical properties.

A 
Density
Solubility 
Electrical Conductivity
Malleability
Melting Point
Boiling Point
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19
Q

Ability of a substance to be rolled or pounded into various shapes

A

malleability

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20
Q

Chemical Properties

A

substances ability to change into a new substance with different properties

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21
Q

Can be observed only as the identity of a s subtance changes

A

Chemical properties

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22
Q

examples of chemical properties

A

reactivity

flammability

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23
Q

what is the difference between a physical property and a chemical property?

A

A physical property can be observed without changing the identity of a substance. A chemical property can be observed only by changing the identity of a substance.

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24
Q

The characteristic properties of a substance do/do not depend on the size of the sample.

A

Do not.

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25
Q

Flammability is an example of a what property?

A

Chemical

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26
Q

Electrical conductivity is as example of a what property?

A

physical

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27
Q

Must new substances be formed when you observe a chemical property?

A

yes

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28
Q

Matter is lost when a candle is burned. T/F

A

False

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29
Q

physical change

A

change that affects one or more physcial property of a substance

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30
Q

Give examples of physical properties that can be changed.

A

appearance
shape
size

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31
Q

Give examples of physical changes.

A 
stretching a rubber band
dissolving sugar in water
cutting hair
melting butter
bending a paper clip
crushing an aluminum can
cutting paper
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32
Q

chemical change

A

when one or more substances change into an entirely new substance with different properties, the process by which substances actually change into a new substance

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33
Q

Give an example of how chemical properties and chemical changes are not the same.

A

burning is a chemical change

flammability is a chemical property

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34
Q

Give examples of how you can tell a chemical change has happened.

A 
production of gas
production of odor
formation of a precipitate
change in color
change in energy (usually, painting something is a physical change but rusting is a chemical change)
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35
Q

law of conservation of mass

A

in ordinary chemical and physical changes, mass is not created or destroyed but isonly transformed into another substance

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36
Q

When water freezes in a glass, how does the amount of matter in the glass change?

A

it doe not change

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37
Q

smallest unit of an element that maintains the properties of that element

A

atoms

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38
Q

element

A

made up of one or more of the same kind of atom chemically combined

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39
Q

compound

A

made up of different kinds of atoms chemically combined

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40
Q

mixture

A

contains a variety of elements and compounds that are not chemically combined with each other

41
Q

pure substance

A

a substance that has definite physical and chemical properties such as appearance, melting point, and reactivity

42
Q

elements and compounds are examples of what?

A

pure substance

43
Q

Can pure substances be formed or broken down by physical changes?

A

no

44
Q

What is required to break bonds of elements?

A

chemical changes

45
Q

How are elements classified?

A

metals
nonmetals
metalloids

46
Q

What is shiny, conducts heat and electricity well, and can be shaped into thin sheets and wires?

A

metals

47
Q

What is not shiny and do not conduct heat or electricity well?

A

nonmetals

48
Q

What has some properties of both metals and nonmetals?

A

metalloids

49
Q

How can compounds be classified?

A

pH
organic or inorganic
role in the body (lipids/proteins/nucleic acids, etc)

50
Q

combination of two or more substances that are combined physically but not chemically, can be separated by physical changes

A

mixture

51
Q

heterogeneous mixture

A

one that does not have a uniform composition

52
Q

homogeneous mixture

A

uniform composition or structure throughout

53
Q

suspension

A

type of heterogeneous mixture in which particles are too large to stay mixed without being stirred or shaken

54
Q

colloids

A

mixture that falls between suspension and solution, particles are spread throughout a liquid or gas but are small and do not settle out quickly

eg: milk & gelatin

55
Q

are colloids homogeneous or heterogeneous?

A

they look homogeneous but are considered heterogeneous

56
Q

solution

A

homogeneous mixture, one substance is dissolved in another substance

57
Q

solid

A
  • substance that has a definite volume and shape

- particles are close together and do not move freely, they vibrate but are fixed in place

58
Q

liquid

A
  • a substance that has definite volume but not a definite shape
  • particles have more kinetic energy
59
Q

gas

A
  • substance without definite volume or shape

- particles have the most kinetic energy of the three states

60
Q

when a liquid becomes a gas at the liquids surface

A

evaporation (eg. puddle drying out)

61
Q

condensation

A

gas becomes a liquid

62
Q

a solid becomes a gas

A

sublimation

63
Q

gas becomes a solid

A

deposition

64
Q

liquid becomes a gas throughout

A

boiling

65
Q

liquid becomes a solid

A

freezing

66
Q

solid becomes a liquid

A

melting

67
Q

T/F When the distance between gas particles increases, the volume of the gas increases

A

True

68
Q

What happens when matter changes state?

A

Energy is gained and lost but the net energy is conserved. A substance must gain energy from the environment or lose energy to the environment but total amount of energy is conserved.

Mass is conserved

69
Q

smallest particle into which an element can be divided and till be the same element

A

atom

70
Q

Can you see an atom with a light microscope?

A

no

71
Q

negatively charged particles

A

electrons

72
Q

What was John Dalton’s theory?

A
  • all matter is made up of atoms
  • atoms cannot be created, divided or destroyed
  • all atoms of a certain element are identical
73
Q

how do the ideas of John Dalton differ from those of Democritus and Aristotle?

A

Dalton’s theory was based on evidence from experiments

74
Q

What did JJ Thompson believe?

A
  • atoms are made of even smaller particles

- found particles within the atom that have a negative charge- became known as electrons

75
Q

Ernest Rutherford

A
  • experiment suggested that atoms have a nucleus

- found that the nucleus is made up of positively charged particles and are called protons

76
Q

Nucleus

A

small, dense center that has a positive charge and is surrounded by moving electrons

77
Q

Niels Bohr

A
  • observations led to a new theory of how electrons in a storm behave
  • believed that electrons move around the nucleus in circular paths
78
Q

What is the atomic theory?

A
  • atoms are basic unit of matter and atoms of each element are unique
  • atoms are made up of electrons and protons
  • nucleus contains uncharged particles called neurons
  • electrons do no move in circular paths around the nucleus but within an area around the nucleus called the electron cloud
79
Q

James Chadwick

A
  • discovered that the nucleus contains uncharged particles called neutrons
  • electron cloud
80
Q

what particles reside in the nucleus?

A

protons and neutrons

81
Q

What charge is the nucleus

A

positive

82
Q

How can you describe atoms?

A

atomic number

mass number

83
Q

number of PROTONS in the nucleus of an atoms

A

atomic number

84
Q

number of PROTONS AND NEUTRONS in an atom’s nucleus?

A

mass number

85
Q

Isotopes

A

atoms of the same element that have different numbers of neutrons

86
Q

Elements in the same ___ on the periodic table have the same number of valence electrons.

A

group

87
Q

Properties of elements within a ___ on the periodic table change in a predictable way from one side of the table to the other.

A

period

88
Q

Elements in the same ___ have similar properties.

A

group

89
Q

rows on the periodic table are known as ___

A

periods

90
Q

Each vertical column of elements from top to bottom on the periodic table is called a ___.

A

group

91
Q

Another name for a group is a ___

A

family

92
Q

What are valence electrons?

A

electrons found in the outermost portion of the electron cloud

93
Q

Describe how valence electrons determine the reactivity of an element.

A

The more valence electrons, the less reactive the element is.

94
Q

Each horizontal row of elements on the periodic table *from left to right” is called a ___

A

period

95
Q

Explain how elements are arranged.

A

According to increasing atomic number.

96
Q

Chemical symbol

A

abbreviation for the elements name

97
Q

Average atomic mass

A
  • weighted average of the masses of all the naturally occurring isotopes of that element
  • number on the bottom of the square
98
Q

Atomic number

A
  • At the top of the square on the periodic table
  • number of protons and neutrons
  • all atoms of the same element have the same atomic number
99
Q

What does the zigzag line on the periodic table represent?

A

separates the metals from the nonmetals

8th Grade (4 decks)

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