Chapter 1 - Chemical foundations

Question 0

measurement

Answer 0

a quantitative observation

Question 1

what are the three fundamental steps to the Scientific Method

Answer 1

Make observations
formulate hypotheses
perform experiments

Question 2

what are the necessary components of a measurement?

Answer 2

a number and a unit

Question 3

how is uncertainty recorded in a measurement?

Answer 3

sig figs–all the certain figures plus the first uncertain one

Question 4

hypothesis

Answer 4

one or more assumptions put forth to explain the observed behavior of nature

Question 5

theory

Answer 5

a set of assumptions put forth to explain some aspect of the observed behavior of matter

Question 6

model

Answer 6

a set of assumptions put forth to explain the observed behavior of matter (in chemistry, usu involve assumptions about the behavior about individual atoms or molecules)

Question 7

natural law

Answer 7

a statement that expresses generally observed behavior

Question 8

law of conservation of mass

Answer 8

mass is neither created or destroyed

Question 9

law of conservation of energy

Answer 9

energy is neither created or destroyed

Question 10

law of definite proportion

Answer 10

a given compound always contains exactly the same proportion of elements by mass

Question 11

law of multiple proportions

Answer 11

when two elements form a series of ompounds, the ratios of the masses of the second element that combine with one g of the first element can always be reduced to small whole numbers

Question 12

What are the 4 components of Dalton’s Theory of Atoms?

Answer 12

all elements are composed of atomons
all atoms of a given element are identical
chemical compounds are formed when atoms combine
atoms are not changed in chemical reactions, but the way they are bound together changes

Question 13

atomic mass (atomic weight)

Answer 13

the weighted average mass of the atoms in a naturally occurring element (Dalton, first to make table of atomic masses)

Question 14

Avogadro’s hypothesis

Answer 14

equal volume of gasses at same temp and pressure have an equal number of atoms

Question 15

cathode-ray tubes

Answer 15

the “rays” emanating rom the negative electrode (cathode) in a partially evacuated tube; a stream of electrons

Question 16

electrons

Answer 16

a negatively charged particle that moves around the nucleus of the atom, mass is 1/1840 of a proton

Question 17

radioactivity

Answer 17

the spontaneous decomposition of a nucleus to form a different nucleus

Question 18

nuclear atom

Answer 18

an atom having a dense center of positive charge (the nucleus) with electrons moving around the outside

Question 19

nucleus

Answer 19

the small, dense center of positive charge in an atom

Question 20

proton

Answer 20

a positively charged particle in an atomic nucleus

Question 21

neutron

Answer 21

a particle in the atomic nucleus with mass virtually equal to the proton’s but with no charge

Question 22

isotopes

Answer 22

atoms of the same element (the same # of protons) with different numbers of neutrons. They have identical atomic numbers but different mass numbers

Question 23

atomic number

Answer 23

the number of protons in the nucleus of an atom

Question 24

mass number

Answer 24

the total number of protons and neutrons in the atomic nucleus of an atom

Question 25

energy

Answer 25

the capacity to do work or to cause heat flow

Question 26

work

Answer 26

force acting over a distance

Question 27

potential energy

Answer 27

energy due to position or composition

Question 28

kinetic energy

Answer 28

1/2mv^2 energy due to the motion of an object; dependent on the mass of the object and the square of its velocity

Question 29

mole

Answer 29

(mol) the number equal to the number of carbon atoms in exactly 12 grams of pure ^12C: Avogadro’s number. One mole represent 6.022 x 10^23 units

Question 30

The Thompson model of the atom

Answer 30

the “plum pudding model”; used the cathode-ray tubes to determine that all atoms had electrons and hypothesized that the electrons were embedded randomly in a diffuse cloud of positive charge like raisins in a plum pudding

Question 31

Millikan experiment

Answer 31

using charged oil drops and voltage, Millikan was able to determine the magnitude of the electron charge

Question 32

Rutherford experiments

Answer 32

by using alpha particles, was able to determine that atoms must have a concentrated positive charge that contains most of the atoms mass

Question 33

the nuclear model

Answer 33

the model of the atom that assumes the nucleus contains protons and neutrons and a cloud of electrons surrounding it

Question 68

mole

Answer 68

a unit of measurement that represents 6.022x10^23 molecules, Avogadro’s number

Question 69

what is the structure of the atom

Answer 69

a small, dense nucleus containing protons and neutrons

electrons that reside outside the nucleus in the relatively large remaining atomic volume