Chemistry

Question 1

matter

Answer 1

has mass and takes up space

Question 2

ground state

Answer 2

most stable state. state in which all electrons are at their lowest possible energy level

Question 3

controlled variable

Answer 3

experimental conditions that remain constant

Question 4

density

Answer 4

mass divided by volume

Question 5

endothermic

Answer 5

energy is added to change state

boil, evaporation, melting, sublimation

Question 6

exothermic

Answer 6

energy loss to change state

(condense, solidify, freeze, deposition

Question 7

BIN MIX

Answer 7

breaking is endothermic-energy in

making is exothermic - energy out

Question 8

atom

Answer 8

smallest unit of a substance that behaves like a substance, mostly empty space

Question 9

energy

Answer 9

the ability to change or to move matter

Question 10

sublimation

Answer 10

change of a substance from a solid directly to a gas

Question 11

electrons

Answer 11

located on the outermost part of the neutron around the nucleus, have a negative charge, experiments with cathode rays let to the discovery of them.

Question 12

atomic number

Answer 12

number of protons in that atom. all atoms of the same element have this.

Question 13

neutron

Answer 13

neutral charge, found in the nucleus

Question 14

proton

Answer 14

positive charge, found in the nucleus of an atom

Question 15

mass number

Answer 15

number of protons plus neutrons

Question 16

Dalton’s atomic theory

Answer 16

atoms of each element are identical in size, mass, and other properties, his theory has been expanded and modified.such as “atoms cannot be divided”
says: in chemical reactions, atoms are combined, separated, or rearranged; all matter is composed of extremely small particles called atoms, and atoms cannot be divided, created or destroyed.
dalton thought that atoms cannot be broken down further . Not apart of his theory: an atom consists of a nucleus and a cloud of electrons. df

Question 17

atomic theory

Answer 17

atoms of the same element may have different masses

Question 18

law of definite proportions

Answer 18

states: any two samples of KC1 have the same ratio of elements, agrees with Dalton’s atomic theory. the fact that every sample of a [articular chemical compound contains the same elements in exactly the same proportions by mass.
if two or more compounds are composed of the same two elements, then the ratio of the masses of the second element that is combined with a certain mass of the first element is always a ratio of small whole numbers.

Question 19

Rutherford

Answer 19

in his experiment, most of the particles passes through the foil. which led him to conclude that atoms contain massive central regions that have a positive charge. Rutherford concluded that atoms were mostly empty space. identified the nucleus of the atom

Question 20

dependent variable

Answer 20

variable that reacts to the independent date

Question 21

constant

Answer 21

factor held constant, kept the same

Question 22

independent variable

Answer 22

variable that is changed

Question 23

physical property

Answer 23

observed with the senses and can be determined without destroying the object

Question 24

chemical property

Answer 24

indicates how a substance reacts with something else. The original substance is fundamentally changed in observing this.

Question 25

solidify

Answer 25

change from a liquid to gas

Question 26

condense

Answer 26

the change from a gas to a liquid

Question 27

sublimation

Answer 27

the change from solid directly to gas

Question 28

deposition

Answer 28

the change from gas directly go solid

Question 29

significant figures

Answer 29

all non 0 numbers are significant, any 0 sandwiched btwn numbers are sig, trailing zeros (on right side) without decimal point are not sig, with decimal point the tailing 0s are sig. lead 0 are not sig.

Question 30

multple proportions

Answer 30

Law which states that when elements combine, they do so in the ratio of small whole numbers (assuming they have the same type of chemical bonds).

Question 31

KHDBDCM

Answer 31

kili, hecto, deka, base unit, deci, centi, milli v

Question 32

definite proportions

Answer 32

states that a chemical compound always contains exactly the same proportion of elements by mass.

Question 33

The theory of Democritus

Answer 33

held that everything is composed of "atoms", which are physically, but not geometrically, indivisible; that between atoms, there lies empty space; that atoms are indestructible; have always been, and always will be, in motion;