Exam Review Flashcards
Matter
• matter is anything that takes up space and has mass
- stuff
Mass
- mass is always
Mass is measured in
• mass is a measure of the amount of matter the object contains
- mass is always constant
- mass is measured in grams of kilograms
Volume
Volume
• the amount of space occupied by the object
What is a substance?
• matter that has a uniform and definite composition is called a substance
Properties of matter
• ask yourself can the properties of the objective observed or measured without changing the objects identity?
• If no -
• If yes -
If no - chemical property
If yes - physical property
Physical Properties of a Substance
- a quality or condition of a substance that can be observed or measured without changing the substances composition
- Describes a matters very existence: color, shape, smell, mass, density, conductivity, malleability
Physical property:
highly reflective, highly conductive, extremely high melting point, non magnetic
Physical property
• does the property depend on the amount of matter present?
• If no - intensive properties - color, density, luster, hardness, temperature, melting point
• If yes - extensive properties - volume, length, mass, weight
- If no - intensive properties - color, density, luster, hardness, temperature, melting point
- If yes - extensive properties - volume, length, mass, weight
Extensive properties -
property that depends on the amount of matter in a sample: volume, weight, mass, length
Intensive properties
a property that depends on type of matter in a sample not the amount: color, density, luster, hardness, temperature
Solid
- a form of matte that has a definite shape and volume
- It doesn’t depend on the shape of its container
- The particles in a solid are packed tightly together
- Particles move very slowly
- Expand only slightly when heated
Liquid
- arrangement of atoms is not rigid or orderly
- Has a definite volume
- Does not have a definite shape
- Flows
- Expand slightly when heated
Gas
- takes the shape of it’s container
- Can expand to fill any volume
- Takes the shape and volume of its container
- Molecules are far apart
- Molecules move freely
- Vapor is the gaseous state of a substance that is generally a liquid or solid at room temperature as water vapor.
During a physical change some properties of a material change, but the composition of the material does ____ change.
Physical changes can be described as ______ and _______
During a physical change some properties of a material change, but the composition of the material does not change. Boil, freeze, condense, break, split, cut, crush.
Physical changes can be described as reversible and irreversible
All physical changes that involve a change from one state to another are __________
Reversible
- solid to liquid
Chemistry (central science)
The study of composition and matter and the changes matter undergoes
Chemistry affects
All aspects of life and most natural events because all living and nonliving things are made of matter
Five traditional areas of Chemistry
- analytical chemistry
- Inorganic chemistry
- Organic chemistry
- Physical chemistry
- Biochemistry
Analytical chemistry
The area of chemistry that focuses on the composition of matter
Inorganic chemistry
The study of chemicals that normally do not contain carbon. Many inorganic chemicals are found in non living things, like construction materials
Organic chemistry
The study of all chemicals containing carbon
Physical chemistry
The area that deals with mechanism, rats and energy transfer that occurs when matter undergoes a change
Biochemistry
The study of processes that take place in living organisms like muscle contraction and digestion
Pure chemistry
The pursuit of chemical knowledge for its own sake
Applied chemistry
Research that is directed toward a practical goal or application
Chemistry as a central science:
Chemistry/overlaps with many other sciences like physicists, biologists, astronomers, and geologists
Elements are composed of tiny particles called
Atoms
Every atom contains a ______ and one or more _________
Nucleus, electrons
The type of products obtained in a chemical reaction is determined by
The electrons in the reacting chemicals
Chemical reactions involve processes in which
Reactants produce products
Kinetic theory -The particles in matter are in
Constant motion
The mole and quantifying matter -
When conducting a chemical reaction you need just the right amount of reacting material, so none is wasted. The measurement is possible using the mole.
Every chemical process uses or produces _______, often in the form of _____
Energy, heat
Changes in quantity called _______ _________ allow you to predict whether a reaction will …..
Free energy, whether a reaction will actually occur under the given conditions
Carbon chemistry
Carbon compounds are the basis of life in all living organisms
Alchemy
Alchemy didn’t provide a logical explanation for the changes in ______ they observed
-Field prior to chemistry that searched for methods to change metals, such as lead into gold
did not provide a logical set of explanatis for the changes in matter they observed
Alchemy spurred the development of ____
- it developed ____ and _____ for working with chemistry
- it developed processes for _______ _____ and _______ _______
- chemistry
- tools and techniques
- separating mixtures and purifying chemicals
- In the late 1700s ________ helped to transform chemistry from a science of _________ to a science of _______ that it is today
- Designed a balance that could measure ______ to the nearest 0.0005 gram
- Demonstrated that _______ is required for a material to burn.
• Lavoisier, observation, measurement
- mass
• Oxygen
Scientific methodology
Involves making observations, proposing and testing hypotheses, and developing theories
Hypothesis
Is a proposed explanation for an observation
In an experiment when one variable changes and all the other remain constant it is called a
Controlled experiment
Independent variable
The variable that is manipulated or purposefully changed
Dependent variable
The variable that is observed and that changes in response to the independent variable
A model
Is a representation of an object or event
Law of conservation of mass
States that there is no detectable change in the quantity of matter during an ordinary chemical reaction
Reasons to collaborate
- Scientists of different disciplines can be brought together to share expertise
- Industry may collaborate with scientists each benefitting
Conflict with collaboration among scientist
Who gets the credit
Ways of communication for scientists
- Journal - scientists establish their records in scientific journals
- most reliable source of information about new discoveries - The internet - major source of information
Extensive properties
The property that depends on the amount of matter in a sample
Intensive properties
Is a property that depends on the type of matter not the amount
Physical changes can be described as
Reversible or irreversible
Mixture
Refers to the physical combination of two or more substances in which the identities are retained
Heterogenous mixture
A mixture in which the composition is not uniform
Ex: skittles
Homogenous mixture
When the composition is uniform throughout
Ex: jello
What is a phase?
How many phases does a heterogeneous mixture have?
How many phases does a homogeneous mixture have ?
- any part of a sample with uniform composition and properties
- heterogeneous has two or more phases
- homogenous has one
Separating mixtures
Mixtures can be separated by recognizing and using the differences in physical properties
- filtration
- distillation
- magnetism
Filtration
Process that separates a solid from a liquid
Distillation
A liquid is boiled to produce a vapor that is then condensed into a liquid
Element
Simplest form of matter that has unique properties
- there are over 100 known elements
Compounds
A substance that contains 2 or more calmly combined is a fixed proportion
Elements cannot be _____ ____
Broken down
_______ can be broken down into simpler substances by chemical means
Chemicals
Breaking down compounds:
- _____ ______ that are used to separate mixtures CANNOT be used to separate a compound into simpler substances
- a ______ change that produces matter with a different composition than the original matter
- physical methods
- chemical
Distinguishing substances and mixtures
- If the composition of a material is _____ the material is a ________
- If the composition of a material may _____ the material is a _____
- fixed, substance
- vary, mixture
Symbols and formulas:
Chemists use _______ symbols to represent _________ and ________ _________ to represent _______
Chemical
Elements
Chemical formulas
Compounds
Each _____ is represented by a one- or two- chemical symbol
Element
First letter is _____ and the second is ______
This represents its
Capitalized, lowercased
Latin name
The periodic table:
The arrangement of elements in Which elements the elements are separated into groups based on?
This allows the comparison of what?
- on a set of repeating properties
- this allows the comparison of one element to another
Periodic table:
There are horizontal rows called what?
The elements are arranged according to what?
There are vertical rows called what?
The elements within a group have similar what
- periods
- atomic numbers
- group
- Similar chemical and physical properties
- During a chemical change what always changes?
- usually one or more _____ is produced during s chemical change
- are they reversible or irreversible
- the composition of matter
- substances
- Irreversible
Recognizing a chemical change:
There are usually four clues that indicate a chemical change
- every chemical changes involves a
- Transfer of energy
- Change in color
- The production of a gas
- The formation of a precipitate
- transfer of energy
Law of conservation of mass
During any chemical reaction, the mass of the product is always equal to the mass of the reactants
During physical changes mass also holds
Constant
How do you write numbers in scientific notation
- Measurement is a quantity that has both a number and a unit
- Measurements are fundamental to the experimental sciences
In scientific notation of a given number is written as the product of two numbers
- Coefficient
2. 10 raised to a power
What does a positive exponent indicate
• A positive exponent indicates how many times the coefficient must be multiplied by 10
Numbers bigger than 10 have what?
• Numbers bigger than 10 have a positive exponent and equals the number of places the decimal has been moved to the left.
A negative exponent indicates
• A negative exponent indicates how many times the coefficient must be divided by 10
Numbers smaller than one have what?
• Numbers smaller than one have a negative exponent and equals the number of places the decimal has been moved to the right.
Accuracy
To evaluate accuracy what must be compare?
is a measure of how close a measurement comes to the actual or true value of whatever is measured
• to evaluate accuracy of a measurement, the measured value must be compared to the correct value
Precision
To evaluate precision what must be compared?
Precision - is a measure of how close a series of measurements are to one another irrespective of the actual value
• To evaluate precision of a measurement you must compare the values of two or more repeated measurements
Accepted value
the correct value for the measurement based on a reliable reference
Experimental value -
The value measured in a lab
Significant figures:
- the significant figures in a measurement include what
Significant figures
• include all of the digits that are known plus a last digit that is estimated
• Significant figures are calculated answers often depend on the number of significant figures in the values used in the calculation
Significant figures:
- Zeros appearing between nonzero digits are:
• leftmost zeros appearing in front of the nonzero digits are: , They act as placeholders
• Leading zeros are
• Zeros at the end of a number and to the right of a decimal point are always
• Trailing zeros count as ________ if there is a decimal
• Zeros at the rightmost end of a measurement that lie to the left of an understood decimal point are __________ if they serve as place holders to show the magnitude of the number
- significant
- not significant
- not significant
- significant
- significant
- not significant
Unlimited significant figures occur in two situations:
- Counting. A munger that is counted is exact
2. Exactly defined quantities such as chosen found in a system of measurement
