CHEM 105 Chapter 1 Quiz

Question 1

atoms

Answer 1

basic submicroscopic particles that constitute the fundamental building blocks of ordinary matter

Question 2

molecules

Answer 2

substances formed when two or more atoms come together (bond) in specific geometric arrangements

Question 3

? determine how matter behaves

Answer 3

atoms and molecules

Question 4

matter can be classified according to ? and ?

Answer 4

its state (physical form) and its composition (the types of particles)

Question 5

matter can be classified into ? or ? depending on if it has one type of particle or not

Answer 5

a pure substance (one type of particle) or a mixture (more than one)

Question 6

a pure substance can be classified into ? or ? depending on if it is separable into simpler substances

Answer 6

element (not separable, e.g. Helium) and compound (separable, e.g. H2O)

Question 7

a mixture can be classified into ? or ? depending on whether or not it is uniform throughout

Answer 7

heterogeneous (not uniform, e.g. wet sand) and homogeneous (uniform, e.g. tea with sugar)

Question 8

element

Answer 8

a substance that cannot be chemically broken down into simpler substances

Question 9

compound

Answer 9

a substance composed of two or more elements in fixed definite proportions

Question 10

key characteristics of the scientific method

Answer 10

observations, formulation of hypothesis, experimentation, formulation of laws and theories

Question 11

observations

Answer 11

descriptions about characteristics/behavior of nature

Question 12

hypothesis

Answer 12

a tentative interpretation or explanation of the observations

Question 13

a good hypothesis is ?, meaning ?

Answer 13

falsifiable: able to be proved wrong

Question 14

a scientific law

Answer 14

a brief statement that summarizes past observations and predicts future ones

Question 15

theory

Answer 15

a well-established hypothesis or set of hypotheses form the basis for a scientific theory; tries to explain not merely what nature does, but why a natural phenomenon happens; validated by experimental results but can never be conclusively proven

Question 16

qualifiable data

Answer 16

observational, subjective in nature (e.g. color, shape)

Question 17

quantifiable data

Answer 17

measurable (empirical), objective in nature; uses equipment capable of generating empirical data with standardized units

Question 18

Dalton’s atomic theory

Answer 18

1. each element is composed of tiny, indestructible particles called atoms
2. all atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements
3. atoms combine in simple, whole-number ratios to form compounds
4. atoms of one element cannot change into atoms of another element; in a chemical reaction, atoms change only the way that they are bound together with other atoms

Question 19

the law of conservation of mass

Answer 19

in a chemical reaction, matter is neither created nor destroyed

Question 20

the law of definite proportions (Joseph Proust)

Answer 20

all samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements

Question 21

the law of multiple proportions (John Dalton)

Answer 21

when two elements (call them A and B) form two different compounds, the masses of element B that combine with one gram of element A can be expressed as a ratio of small whole numbers

Question 22

the discovery of the electron (JJ Thompson’s cathode ray experiment)

Answer 22

Thompson was able to measure the charge-to-mass ratio of cathode ray particles by deflecting them using electric and magnetic fields, which are electrons

Question 23

the charge-to-mass value of the electron as measured by JJ Thompson

Answer 23

-1.76 x 10^8 coulombs per gram

Question 24

determining the charge of the electron (Robert Millikan’s oil drop experiment)

Answer 24

determined the mass of oil drops from their radii and density; the charge of any oil drop was always a whole number multiple of -1.60 x 10^-19 C

Question 25

the fundamental charge of a single electron

Answer 25

-1.60 x 10^-19 C

Question 26

JJ Thompson's model

Answer 26

plum pudding: the negatively charged electrons were small particles held within a positively charged sphere

Question 27

conclusions of Rutherford's gold foil experiment

Answer 27

some particles were deflected, so matter must not be as uniform as it appears; it must contain large regions of empty space dotted with small regions of very dense matter (nuclear model)

Question 28

nuclear theory of the atom

Answer 28

1. most of the atom's mass and all of its charge are contained in a small core called a nucleus 2. most of the volume of the atom is empty space, throughout which tiny, negatively charged electrons are dispersed 3. there are as many negatively charged electrons outside the nucleus as there are positively charged particles (protons) in side in the nucleus, so that the atom is electrically neutral

Question 29

Rutherford's student ? demonstrated that the previously unaccounted for mass in the nucleus was due to ?

Answer 29

James Chadwick; neutrons

Question 30

the mass of the ? and the ? are the most similar

Answer 30

proton and neutron

Question 31

the charge of the ? and ? are the most similar

Answer 31

proton and electron, though they have opposite signs

Question 32

the most important number to the identity of an atom is ?

Answer 32

Z, its atomic number (the number of protons in its nucleus)

Question 33

isotopes

Answer 33

all atoms of a given element have the same number of protons, but not necessary the same number of neutrons

Question 34

the sum of the ? and ? in an atom is its mass number, represented by the symbol A

Answer 34

protons and neutrons

Question 35

the notation for an isotope is either ? or ?

Answer 35

X (the chemical symbol) with its mass number (A) to the top left and its atomic number (Z) to the bottom left of it or the chemical symbol (X) or name, hyphen, mass number (A) [e.g. Ne-20 or neon-20]

Question 36

natural abundance

Answer 36

the relative amount of each different isotope in a naturally occurring sample of a given element is roughly constant; these % are called the natural abundance of the isotopes

Question 37

ions

Answer 37

in chemical changes, atoms can lose or gain electrons and become charged particles called ions

Question 38

cations

Answer 38

positively charged ions

Question 39

anions

Answer 39

negatively charged ions

Question 40

atomic mass

Answer 40

the average mass of the isotopes that compose that element; calculated by the sum of each (fraction of isotope n) * (mass of isotope n), with the fraction being the decimal value of the natural abundance % and the mass being the mass number of the isotope

Question 41

mass spectrometry

Answer 41

the masses of atoms and the % abundance of isotopes of elements are measured using this technique

Question 42

1 mol

Answer 42

6.022 x 10^23 atoms