Ch1 - Matter, Measurement, and Problem Solving

Question 1

Matter

Answer 1

anything that takes up space and has mass

Question 2

Mass

Answer 2

the substance which makes up the physical world; mass is made of atoms and is constant

Question 3

weight

Answer 3

a measure of mass that depends on gravity; weight changes depending on where you are measuring

Question 4

chemistry

Answer 4

the study of matter, it’s behavior, and interactions

Question 5

modern science

Answer 5

empirical observation and experiment. science is widely used to guide the development of technology

Question 6

scientific method

Answer 6

1. Make careful observations and collect data
2. Propose a hypothesis to explain the data
3. Test the hypothesis by experimentation
4. Accept or reject the hypothesis

Question 7

hypothesis

Answer 7

an educated guess. If strongly supported by data a hypothesis may become a theory.

Question 8

scientific theory

Answer 8

A proposed explanation for tested hypotheses and scientific laws that presents a model of how nature works and can predict future behavior. A theory is usually complex and explains “how” or “why.”

Question 9

scientific law

Answer 9

summarizes past observations and predicts what will happen. Usually simple and gives the “what.”

Question 10

atomic theory

Answer 10

1. Elements are made up of atoms that cannot be divided
2. atoms of the same element have the same chemical properties
3. Atoms of different elements have different properties
4. Compounds are formed when two or more atoms of two or more elements combine

Question 11

who devised the atomic theory?

Answer 11

John Dalton in 1808

Question 12

evidence for Dalton’s atomic theory

Answer 12

1. the law of conservation of mass
2. the law of constant composition
3. The law of multiple proportions

Question 13

the law of conservation of mass

Answer 13

in a chemical reaction mass is neither created nor destroyed

Question 14

law of constant composition

Answer 14

a compound always consists of the same elements, in the same proportion to each other by mass (number of atoms). Allows for chemical formula.

Question 15

the law of multiple proportions

Answer 15

atoms combine with each other in ratios of small whole numbers

Question 16

solids

Answer 16

have a definite shape and volume - they vary in their hardness and brittleness from substance to substance. Solids are not compressible.

Question 17

liquids

Answer 17

have a definite volume and are not compressible. Liquids do not have definite shape; they will take the shape of the bottom of their containers and will spread out on a flat surface.

Question 18

gases

Answer 18

do not have either a definite volume or a definite shape; they take both the volume and the shape of their container and are easily compressible.

Question 19

physical change

Answer 19

substances that change their form or phase but not their essential nature.

ex: melting, boiling, dissolving, and grinding into a powder.

Question 20

chemical change

Answer 20

chemical reaction - one set of substances (reactants) is transformed into another set of substances (products).

ex: combustion

Question 21

nuclear reaction

Answer 21

deals with radioactivity

ex: nuclear decay

Question 22

compound

Answer 22

a pure substance composed of two or more elements

Question 23

two properties of a compound

Answer 23

1. has constant composition - always the same elements in always the same proportions.
2. in order to separate a compound into its elements, chemical reactions must be used. It is often easier to make a compound from its elements than to separate (resolve) a compound into its elements.

Question 24

mixture

Answer 24

consists of any substances mixed together in any proportion. Composition in a mixture is NOT constant.

Question 25

separating a mixture into its components

Answer 25

mixtures do not require chemical reactions to separate them into their components. physical methods such as distillation, filtration, crystallization, and chromatography will often do the job.

Question 26

two types of mixtures

Answer 26

homogeneous mixtures and heterogeneous mixtures

Question 27

homogeneous mixtures

Answer 27

May differ in composition from sample to sample, the each sample is uniform. All mixtures of gases are homogeneous. Homogeneous mixtures are usually solutions.

Question 28

Solutions

Answer 28

a solution is made up of a solvent, the substance present in the largest amount, and one or more solutes. Liquid solutions may be colored or colorless, but are transparent. There are also solid solutions such as brass.

Question 29

heterogeneous mixture

Answer 29

heterogeneous mixtures are not uniform throughout. Often the different components can be easily seen with the naked eye.

Question 30

distillation

Answer 30

a method used to separate the components of a mixture of liquids.

Question 31

energy

Answer 31

the capacity to do work

Question 32

work

Answer 32

the action of force through a distance

Question 33

kinetic energy

Answer 33

the energy of motion

Question 34

potential energy

Answer 34

the energy of position or composition - stored energy - chemical energy

Question 35

thermal energy

Answer 35

a type of kinetic energy associated with heat

Question 36

law of conservation of energy

Answer 36

Energy may flow from one object to another, or change from one kind of energy to another, but the total quantity of energy does not change.

Question 37

formula used to convert from Celsius to Fahrenheit (°F = …)

Answer 37

°F = (°C • 1.8) + 32

Question 38

formula used to convert from Fahrenheit to Celsius (°C = …)

Answer 38

°C = (°F - 32) / (1.8)

Question 39

formula to convert Celsius to Kelvin

Answer 39

K = °C + 273.15

Question 40

formula for density

Answer 40

d = m / V

Question 41

specific gravity

Answer 41

the density of a substance divided by the density of water (usually 1.00g / mL). Specific gravity has no units.

Question 42

extensive properties

Answer 42

properties of a substance which depend on the quantity of the material.

Ex: Mass and volume

these are NOT useful in identifying a substance.

Question 43

intensive properties

Answer 43

properties of a substance which are independent of sample size.

Ex: Density, solubility, boiling point

these ARE useful in identifying a substance.