Chemistry Chapter 1 And 2 Test

Front 1

explain the process called the scientific method

Back 1

1. state the problem and collect data (make observations)
2. formulate hypothesis (a possible explanation)
3. perform experiments

Front 2

why is chemistry called the central science

Back 2

most of the phenomena that occur in the world around us involve chemical changes, changes where one or more substances become different substances

Front 3

recognize and apply la safety rules and procedures

Back 3

study contract

Front 4

describe the difference between qualitative and quantitative observations

Back 4

quantitative - has some sort of number measurement
qualitative - is some sort of physical quality - no number

Front 5

make appropriate measurements of mass, length temperature and volume

Back 5

read book

Front 6

record measurements to the correct number of digits

Back 6

read book

Front 7

understand and apply teh basic concepts of writing a lab report

Back 7

study lab report directions

Front 8

describe the difference between accuracy and precision

Back 8

accuracy - how close your answer is to the right answer
precision - how close your answers are to each other, different trials to others

Front 9

describe and give examples of states of matter

Back 9

gas
liquid
solid
plasma

Front 10

distinguish matter between elements, compounds, homogeneous mixtures or heterogenous mixtures

Back 10

compounds - atoms are bonded together in specific ways; made up of 2 or more different types of atoms
elements - made up of only one atom
homogeneous mixtures - also known as a solution; the same through out - all regions have the same amount and properties
heterogeneous mixtures - contains regions that have different properties from those of other regions

Front 11

classify properties and changes in matter as physical or chemical

Back 11

study book

Front 12

determine density of objects

Back 12

mass/volume

Front 13

calculate the percent error of a measurement

Back 13

experimental value minus accepted value divided by accepted value times 100

Front 14

describe ways mixtures can be separated

Back 14

distillation - separating by boiling, which changes teh water to steam and leaves the minerals behind as solids. if we collect and cool the steam, it condenses to pure water; we are separating but not changing the individual substances
filtration - pour mixture onto mesh, such as filter paper, which allows the liquid to pass through and leaves the solid behind

Front 15

accuracy

Back 15

how close your answer is to the right answer

Front 16

alloy

Back 16

mixtures of metals

Front 17

chemical change

Back 17

involves a change in the fundamental components of the substance; a given substance changes into a different substance or substances. cannot be reversed

Front 18

chemical property

Back 18

a substances/ ability to form a new substance(s)

Front 19

compound

Back 19

substances made by bonding atoms together in specific ways; contain 2 or more different types of atoms bound together in a particular way; consists of the same particles throughout

Front 20

density

Back 20

a property of matter representing the mass per unit volume

Front 21

distillation

Back 21

separates a mixture based on their boiling point

Front 22

elements

Back 22

a substance made of only one type of atom

Front 23

filtration

Back 23

separates a mixture based on the size of particles and the phase

Front 24

gas

Back 24

has no fixed volume or shape. uniformly fills any container

Front 25

graduated cyclinder

Back 25

a cyclinder in which you can meausre volume of a substance (record to hundredths place)

Front 26

heterogeneous mixture

Back 26

contains regions that have different properties from those of other regions. (is mixed unevenly in regions)

Front 27

hypothesis

Back 27

a possible explanation for the observation

Front 28

liquid

Back 28

has a definite volume but takes the shape of its container

Front 29

mass

Back 29

the quantity of matter in an object

Front 30

mixture

Back 30

something that has variable composition. ex: wood is a mixture; soda is a mixture - 2 or more substances mixed together with no certain ratio and different combinations

Front 31

physical change

Back 31

involves a change in one or more physical properties, but no change in the fundamental components that make up the substance. cannot be reversed. most common changes are solid -> liquid -> gas

Front 32

physical property

Back 32

the physical look of something (ie. a person - blue eyes, brown hair) (ie. a substance - odor, color, volume)

Front 33

plasma

Back 33

It comprises the major component of the Sun. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.

Front 34

precision

Back 34

compares closeness of the experimental values to one another

Front 35

pure substance

Back 35

either elements or compounds; always have the same composition

mixtures: 2 or more pure substances

Front 36

scientific method

Back 36

the process that lies at the center of scientific inquiry

Front 37

solid

Back 37

is rigid. has a fixed shape and volume

Front 38

solution

Back 38

a mixture in which 1+ substances are evenly distributed in another substance

Front 39

triple beam balance

Back 39

a scale that measures grams

Front 40

volume

Back 40

quantity of a 3 dimensional space occupied by a liquid, solid, or gas

Front 41

percent error

Back 41

my answer minus the accepted value divided by the accepted value times 100 = how much percent you were off

Front 42

qualitative

Back 42

do not involve a number but a description

Front 43

quantitative

Back 43

involve a number

Front 44

colloid

Back 44

won't settle but appears opaque or scatters light (milk)

Front 45

suspension

Back 45

mixes but settles at like the bottom (medicine, dressing)

Front 46

density should be measured in

Back 46

millimeters per cubic inches

Front 47

The rule for recording measurements from analog instruments properly is to ____.

Back 47

record all exact digits, followed by one estimated digit

Front 48

mixtures can be separated by using

Back 48

physical changes

Front 49

what do you round to on triple beam balance

Back 49

hundredths

Front 50

what do you round to in graduated cylinder

Back 50

tens