Chemistry 152T Test #1 - Textbook Flashcards (Chapters 1-3)

Question 1

What is chemistry?

Answer 1

The study of the composition, properties, and transformations of matter - particularly concerned with the way substances change, often dramatically, when they react with each other in chemical reactions.

Question 2

What is an observation?

Answer 2

A statement that accurately describes something we see, hear, taste, feel, or smell.

Question 3

The observations we make while performing experiments are referred to as _______?

Answer 3

Data.

Question 4

What is a scientific law?

Answer 4

A broad generalization based on the results of many experiments - Only states what happens - does not provide explanations.

Question 5

What do scientists create to explain observed laws?

Answer 5

Theoretical models - Mental pictures.

Question 6

What is a theory?

Answer 6

A tested explanation of the behavior of nature - we can never prove absolutely that it is correct.

Question 7

What does macroscopic mean?

Answer 7

Visible.

Question 8

What is matter?

Answer 8

Anything that occupies space and has mass.

Question 9

Explain mass vs. weight.

Answer 9

Mass refers to how much matter there is in a given object, whereas weight refers to the force with which the object is attracted by gravity.

Question 10

What are chemical reactions?

Answer 10

Transformations that alter the chemical compositions of substances.

Question 11

What is decomposition?

Answer 11

A type of chemical reaction in which one substance is changed into two or more others.

Question 12

What are elements?

Answer 12

Substances that cannot be decomposed into simpler materials by chemical reactions.

Question 13

What is a compound?

Answer 13

A substance formed from two or more different elements, in which the elements are always combined in the same, fixed proportions by mass.

Question 14

Elements and compounds are examples of _______________________.

Answer 14

Pure substances.

Question 15

What is a pure substance?

Answer 15

Elements and compounds are examples of this - Always the same regardless of it’s source.

Question 16

What makes mixtures different than elements and compounds?

Answer 16

It can have variable compositions.

Question 17

What is a homogeneous mixture?

Answer 17

Has the same properties throughout the sample (Example: Sugar water) - Sometimes can be called a solution (like the example).

Question 18

What is a heterogeneous mixture?

Answer 18

Consists of two or more regions, called phases, that differ in properties (Example: Olive oil and vinegar in a salad dressing).

Question 19

What type of mixture is ice and liquid water?

Answer 19

A two phase heterogeneous mixture in which the phases have the same chemical composition but occur in different physical states.

Question 20

What is a physical change?

Answer 20

A change where no now chemical substance form - Process of creating a mixture is a physical change - can be separated easily.

Question 21

What is a chemical change?

Answer 21

The formation of a compound - chemical makeup of the substances involved are changed (Example: Fools gold).

Question 22

What two laws were established after the atom was discovered?

Answer 22

The law of definite proportions, and the law of conservation of mass.

Question 23

What is the law of definite proportions?

Answer 23

In any chemical compound, the elements are always combined in a definite proportion by mass - Also called law of definite composition.

Question 24

What is the law of conservation of mass?

Answer 24

Mass is neither lost nor created during a chemical reaction.

Question 25

Describe Dalton's Atomic Theory.

Answer 25

1) Matter consists of tiny particles called atoms 2) In any sample of a pure element, all the atoms are identical in mass and other properties. 3) The atoms of different elements differ in mass and other properties. 4) When atoms of different elements combine to form compounds, new and more complex particles form. However, in a given compound, the constituent atoms are always present in the same fixed numerical ratio. 5) Atoms are indestructible. In chemical reactions, the atoms rearrange but they do not themselves break apart.

Question 26

True or False? Atoms of different elements have different sizes.

Answer 26

True.

Question 27

What are molecules?

Answer 27

Two or more atoms combined together.

Question 28

What are diatomic molecules?

Answer 28

Molecules composed of 2 atoms each - frequently found in nature such as with hydrogen, oxygen, nitrogen, and chlorine.

Question 29

What is a subscript?

Answer 29

A number written next to the chemical symbol, used to indicate the number of atoms in a molecule. (Example: H2O - 2 is the subscript).

Question 30

What is a chemical formula?

Answer 30

Used to describe chemical substances - symbols are used to represent atoms of the elements present - Most important characteristic of a compounds formula is that it specifies the atomic composition of the substance.

Question 31

What are two of the three-dimensional representations of molecules?

Answer 31

1) Ball and stick model - spheres representing atoms are connected by sticks that indicate the connections between the atoms. 2) Space-filling model - Shows the relative sizes of the atoms and how they take up space with the molecule.

Question 32

What are hydrates?

Answer 32

Compounds whose crystals contain water molecules in fixed ratios.

Question 33

What is the law of multiple proportions?

Answer 33

Whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.

Question 34

What are reactants and products in a reaction?

Answer 34

Reactant - substance present before reaction begins. | Product - substance present after reaction is complete.

Question 35

What is the first 2 in 2H2O called (The two in the front)?

Answer 35

Coefficient.

Question 36

How do we balance an equation, and why do we do this?

Answer 36

We balance an equation by adjusting the coefficients in front of reactant and product molecules in order to balance them out. We do this because matter can not be created nor destroyed, as per the law of conservation of mass.

Question 37

What is synthesis with elements and compounds?

Answer 37

When compounds become elements.

Question 38

Why do we use properties in chemistry?

Answer 38

To identify materials, and distinguish one substance from another.

Question 39

What is a physical property?

Answer 39

A property that can be observed without changing the chemical makeup of a substance (Example: Color, Conductivity, Melting point).

Question 40

What are the three states of matter? Describe them.

Answer 40

1) Solid - definite shape and volume. 2) Liquid - definite volume and indefinite shape 3) Gas - No definite shape or volume

Question 41

Gases are ____________ and ______________?

Answer 41

Compressible and Expandable.

Question 42

What a chemical property?

Answer 42

Describes a chemical change (or reaction) that a substance undergoes.

Question 43

Give an example of a chemical and physical change.

Answer 43

Chemical Change - Oxidation reaction, burning, Iron rusting, etc. Physical Change - Ice melting.

Question 44

What are intensive properties? Give examples, and explain.

Answer 44

Intensive properties are independent of sample size - doesn't matter how much of the substance you have - these will never change. Examples are color, melting point, boiling point, freezing point, chemical properties.

Question 45

What are extensive properties?

Answer 45

Extensive properties are dependent on sample size - Example is mass.

Question 46

What is the difference between qualitative and quantitative observations?

Answer 46

Qualitative does not involve numerical data, whereas quantitative does.

Question 47

What are the SI Base units and their symbols?

Answer 47

``` Length - meter (m) Mass - kilogram (kg) Time - second (s) Electric current - ampere (A) Temperature - kelvin (K) Amount of substance - mole (mol) Luminous intensity - candela (cd) ```

Question 48

The zero point on the Kelvin scale is called ____________. Why?

Answer 48

Absolute zero - Because it is nature's lowest temperature.

Question 49

Trailing zeros are always counted as significant, if the number _______________.

Answer 49

Has a decimal point.

Question 50

Zeros to the left of the first nonzero number are _____________.

Answer 50

never counted as significant - THIS IS ALWAYS THE CASE, EVEN WITH A DECIMAL!!

Question 51

Zeros on the end of a number that does not have a decimal point are ________________.

Answer 51

Not significant.

Question 52

What is dimensional analysis?

Answer 52

A method of conversion where you multiply (given quantity) times (conversion factor) = (desired quantity).

Question 53

What is a conversion factor?

Answer 53

A fraction formed from a valid equality or equivalence between units, and is used to switch from one system of measurement and units to another.

Question 54

1 gram is also equal to ____________?

Answer 54

1 cm^3

Question 55

What is the formula for specific gravity?

Answer 55

Density of a substance/ Density of water. | *** The units for the two densities must be the same so that specific gravity will be a dimensionless number

Question 56

Atoms are composed of _________ particles.

Answer 56

Subatomic.

Question 57

A cathode is _________, whereas an anode is _______.

Answer 57

Negative. | Positive.

Question 58

Describe Thomson cathode ray tube.

Answer 58

He used this to measure the charge-to-mass ratio for the electron (This value is -1.76 times 10^8 coulombs/gram.

Question 59

Describe Millikan's oil drop experiment.

Answer 59

Electrons, which are ejected from molecules in the air by the X rays, are picked up by very small drops of oil falling through the tiny hole in the upper metal plate. By observing the rate of fall of the charged oil drops, with and without electrical charges on the metal plates, Millikan was able to calculate the charge carried by an electron.

Question 60

Describe Rutherford's gold foil experiment.

Answer 60

Most alpha particles went right through the gold foil, however some were deflected by foil - because alpha particles have same positive charge as other particles in the atoms. - Discovered the nucleus.

Question 61

All atoms of a particular element have the same number of ____________.

Answer 61

Protons.

Question 62

Atomic number is ______________.

Answer 62

How many protons are in the nucleus of an atom.

Question 63

What is the isotope mass number equal to?

Answer 63

of protons + # of neutrons.

Question 64

How do you calculate the mass contribution of x when dealing with average atomic masses from isotopic abundances?

Answer 64

Mass contribution of x = (total mass of x) * ((percentage of x)/(100%))

Question 65

The rows in the periodic table are called ______.

Answer 65

Periods.

Question 66

The vertical columns in the periodic table are called __________.

Answer 66

Groups.

Question 67

What are some properties of metals?

Answer 67

Metallic luster, malleability (ability to be hammered or rolled into thin sheets), ductility (the ability to be drawn into wire), conduct electricity.

Question 68

Metalloids tend to be ______________.

Answer 68

Semiconductors.

Question 69

What is an ionic compound?

Answer 69

Generally formed by metal and nonmetal components reacting together - Metal atoms lose one or more electrons to become positively charged ions (CATION), and nonmetal atoms gain one or more electrons to become negatively charged ions (ANION).

Question 70

What is a molecular compound?

Answer 70

Formed when nonmetallic elements combine.

Question 71

The study of organic chemistry begins with ___________.

Answer 71

Hydrocarbons - Compounds of hydrogen and carbon.

Question 72

The first 6 members of the hydrocarbons are called ____________.

Answer 72

The alkane series.