quimica TEST #1 CHAPTER 1

Question 1

Chemistry is ….

Answer 1

the study of the composition, properties, and interactions of matter.

Question 2

Attempts to understand the behavior of matter extend back more than ____

Greeks: Matter consists of:

Alchemists attempted to transform “base metals” into :

Answer 2

2500 years.

• four elements; earth, air, fire, and water.

“noble metals”.

Question 3

Chemistry is a science based on :

Chemists often formulate a : _______ , ______

The laws of science summarize :

Theory :

Answer 3

-observation and experimentation.

-hypothesis – a tentative explanation of observations.

-a vast number of experimental observations and describe or predict some facet of the natural world.

-A well-substantiated, comprehensive, testable explanation of a particular aspect of nature.

Question 4

Chemists study and describe the behavior of matter and energy in :

1) The _____ ____:

which is ?

2) The ______:
is…

3) The _______:
is…

Answer 4

-three different domains.

1) macroscopic domain: Things that are large enough to be sensed directly by human sight or touch.

2)microscopic domain: Things that are only visible through a microscope.

3) symbolic domain : Chemical symbols.

Question 5

Moisture in the air, icebergs, and the ocean represent water in the macroscopic domain.

At the molecular level (microscopic domain), gas molecules are far apart and disorganized, solid water molecules are close together and organized, and liquid molecules are close together and disorganized.

The formula H2O symbolizes water, and (g), (s), and (l) symbolize its phases. Note that clouds are actually comprised of either very small liquid water droplets or solid water crystals; gaseous water in our atmosphere is not visible to the naked eye, although it may be sensed as humidity.

Question 6

Matter is:

The three most common states or phases of matter:
1)

2) 

3)

Answer 6

-Anything that occupies space and has mass.

1) A solid is rigid and posses a definite shape.

2) A liquid flows and takes the shape of its container. Forms horizontal surface. Has fixed volume.

3) A gas takes both the shape and volume of its container.

Question 7

Plasma is…
Plasma has unique :

Plasma is found in :

Naturally:
Man-made:

Answer 7

-A gaseous state of matter that contains an appreciable amount of electrically charged particles.

-properties distinct from ordinary gases.

-certain high temperature environments.

-Stars, lightning.

-Television screens.

Question 8

Mass is

Weight refers to:

An object’s mass is:

Answer 8

-a measure of the amount of matter in an object.

-the force that gravity exerts on an object.

-the same on the earth and the moon but its weight is different.

Question 9

Law of conservation of matter:

The law is true for both____

Answer 9

-There is no detectable change in the total quantity of matter present when matter converts from one type to another.

-chemical and physical changes.

Question 10

An element is a type of:

The known elements are :

There are more than—

___ of these occur naturally

_________ have been created in laboratories

Answer 10

-pure substance that cannot be broken down into simpler substances by chemical changes.

-displayed in a chart known as the periodic table.

• 100 known elements

-90
-Two dozen or so

Question 11

Atom :

Idea first proposed by Greek philosophers, ____ and _____, in the _______

_____ century,__________________ supported this hypothesis with ….

Molecule :

Answer 11

-The smallest particle of an element that has the properties of that element and can enter a chemical combination.

-Leucippus and Democritus; 5th century BCE.

-19th century, John Dalton of England supported this hypothesis with quantitative measurements.

-Consists of two or more atoms connected by strong forces known as chemical bonds.

Question 12

Only a few elements exist as :

Most elements exist as _______________ where …..

examples:

Answer 12

-individual atoms.

-Most elements exist as molecules where two or more atoms of the same element are bonded together.

oxygen, sulfur, phosphorus, hydrogen

Question 13

Many molecules consist of…

examples:

Atoms in all types of molecules move as :

Answer 13

-two or more atoms of different elements.

water, carbon dioxide, and glucose consist of combinations of atoms of different elements.

a unit.

Question 14

Pure substances have :

-____________ : pure substance that…

Consist of ….
Examples:

_______________: pure substances that:

Consist of..
Examples:

The properties of compounds are different from ….

Answer 14

-constant composition.

Elements – Pure substance that CANNOT be broken down into simpler substances by chemical changes.
Consist of one type of element.
Examples: Gold (Au), Phosphorus (P4), Oxygen (O2)

Compounds – Pure substances that CAN be broken down into simpler substances by chemical changes.
Consist of two or more types of elements chemically bonded.
Examples: H2O, C6H12O6, AgCl
The properties of compounds are different from the uncombined elements making up the compound.

Question 15

Upon heating, the compound, mercury (II) oxide, is broken down into…

Answer 15

its elements, mercury and oxygen.

Question 16

A mixture is composed of :

Evaporation is an example of a _____

There are two types of mixtures:

Answer 16

two or more types of matter that can be present in varying amounts and can be separated by physical changes.

physical change.

homogenous mixtures and heterogeneous mixtures.

Question 17

A homogenous mixture exhibits a :

Another name for a homogenous mixture is :

A heterogeneous mixture has a composition that:

Answer 17

uniform composition and appears visually the same throughout.

a solution.

varies from point to point.

Question 18

Depending on ____________, a given substance can be classified as a _________ mixture, a ___________ mixture, a ___________, or an __________.

Answer 18

Depending on its properties, a given substance can be classified as a homogeneous mixture, a heterogeneous mixture, a compound, or an element.

Question 19

properties:

A physical property is a

Examples:

Answer 19

characteristics that enable us to distinguish one substance from another

characteristic of matter that is not associated with a change in its chemical composition.

density, color, hardness, melting and boiling points, and electrical conductivity.

Question 20

A physical change is a

Answer 20

change in the state or properties of matter without any accompanying change in its chemical composition.

Wax undergoes a physical change when solid wax is heated and forms liquid wax.

Steam condensing inside a cooking pot is a physical change, as water vapor is changed into liquid water.

Question 21

chemical property:

Examples:

Answer 21

The change of one type of matter into another type (or the inability to change)

flammability, toxicity, acidity, reactivity, and heat of combustion.

Question 22

Extensive property:
Examples:

Intensive property:
Examples:

Answer 22

Extensive property
Depends on the amount of matter present.
Examples: mass, volume, heat

Intensive property
Does not depend on the amount of matter present.
Examples: density, temperature

Question 23

Measurements provide the information that is the basis of most of the:

Every Measurement provides three kinds of information:

1)

2)

3)

Answer 23

hypotheses, theories, and laws in chemistry.

1) The size or magnitude of the measurement - A Number

2) A standard of comparison for the measurement - A Unit

3) An indication of the uncertainty of the measurement.

Question 24

Without units a number can be

In chemistry we use an updated version of the metric system known as the

Used since:

Answer 24

meaningless or confusing!

International System of Units or SI Units.

1964

Question 25

Base SI unit for mass:

It is now defined by a certain…

One kilogram is about ____ pounds (lbs.)

Answer 25

kilogram

cylinder of platinum-iridium alloy, which is kept in France.

2.2 pounds (lbs.)

Question 26

SI units for volume

Volume is…

The standard SI unit for volume is …….., which is derived from the SI base unit of length.

Other units for volume are ….

1 dm3 =

1 cm3 =

Answer 26

the measure of the amount of space occupied by an object.

the cubic meter (m3)

the liter (L) and milliliter (mL).

1 dm3 = 1 L

1 cm3 = 1 mL

Question 27

The density of a substance is the…

The standard SI unit for density is the…

Commonly used density units based on state of matter:

Answer 27

ratio of the mass of a sample of the substance to its volume.

kilogram per cubic meter (kg/m3).

g/cm3 (solids, liquids)
g/L (gases)

Question 28

__________ is the only type of measurement that is free from uncertainty.

The result of a __________ measurement is an …

The numbers for defined quantities are also exact.

1 foot is exactly __ inches
1 inch is exactly _______ cm
1 gram is exactly ______ kg

Answer 28

Counting

-counting, example of an exact number.

1 foot is exactly 12 inches
1 inch is exactly 2.54 cm
1 gram is exactly 0.001 kg

Question 29

Quantities derived from measurements other than counting are …

There are always _______________ of the measurement process used.

A measured number must be reported in a way to indicate its __________

In general, when recording a measurement you are allowed to ….

Answer 29

uncertain to varying extents.

practical limitations

uncertainty.

estimate one uncertain digit.

Question 30

All of the digits in a measurement, including the uncertain last digit, are called _________

Frequently we need to know the number of significant figures in a measurement reported by someone else.

Answer 30

significant figures

Question 31

Numbers that are always significant:
Nonzero digits
Captive zeros
Trailing zeroes
When they are to the right of the decimal place.
When in Scientific Notation.

Numbers that are always not significant.
Leading zeros
Trailing zeros
When they are to the left of the decimal place.

Question 32

When we add or subtract numbers, we should round the result to the same number of decimal places as:

• (the least precise value in terms of addition and subtraction).

Answer 32

the number with the least number of decimal places

Question 33

When we multiply or divide numbers, we should round the result to the same number of digits as the :

• (the least precise value in terms of multiplication and division).

Answer 33

number with the least number of significant figures

Question 34

volume of a rectangular

Answer 34

V = l × w × d

Question 35

Measurements are said to be precise if :

A measurement is considered accurate if :

Answer 35

they yield very similar results when repeated in the same manner.

it yields a result that is very close to the true or accepted value.

Question 36

The mathematical approach is known as :

Dimensional analysis is based on the :

A conversion factor or unit conversion factor is a :

Example: The lengths 2.54 cm and 1 in. are equivalent.

Answer 36

dimensional analysis.

premise that the units of quantities must be subjected to the same mathematical operations as their associated numbers.

ratio of two equivalent quantities expressed with different measurement units.

Question 37

Temperature refers to the:

Celsius scale
Water freezes at ____°C
Water boils at ____°C

• Fahrenheit scale
  Water freezes at ____°F
  Water boils at ____°F

100 °C covers the same temperature interval as 180 °F.

formula:

Answer 37

hotness or coldness of a substance.

Celsius scale
Water freezes at 0 °C
Water boils at 100 °C

• Fahrenheit scale
  Water freezes at 32 °F
  Water boils at 212 °F

ºF =9/5 x ºC +32

Question 38

The SI unit of temperature is the :

Unlike the Celsius and Fahrenheit scales, the kelvin scale is an :

Zero kelvin corresponds to the :

Kelvin scale
Water freezes at ____K
Water boils at _____ K

100 °C covers the same temperature interval as 100 K.
formula

Answer 38

kelvin (K).

absolute temperature scale.

lowest temperature that can theoretically be achieved.

Water freezes at 273.15 K
Water boils at 373.15 K

ºK = ºC+273.15