Unit 1 Flashcards
Anything that has mass and occupies space
Matter
Study of universe and origins
Cosmology
The property that defines the quantity of matter in an object
Mass
The capacity to do work
Energy
Study of the composition, structure, and properties of matter and of energy consumed or given off when matter undergoes change
Chemistry
What are the two principal categories of matter?
Pure substances and mixtures
Matter that has a constant composition and cannot be broken down to simpler matter by any physical process
Substance
Transformation of a sample of matter (change in physical state) that doesn’t alter chemical identity of substances in sample
Physical process
Combination of pure substances in variable proportions in which the individual substances retain their chemical identities and can be separated by physical process
Mixture
Components distributed uniformly throughout and have no visible boundaries or regions
Homogeneous mixture
Components not distributed uniformly- contains distinct regions of different compositions
Heterogeneous mixture
Pure substance that cannot be separated into simpler substances by any chemical process
Element
Pure substance composed of 2+ elements bonded together in fixed proportions and that can be broken down into those elements by some chemical process
Compound
Transformation of 1+ substances into different substances
Chemical reaction
All samples of a particular compound contain the same elements combined in the same proportions
Law of constant composition
Smallest particle of an element that retains the chemical characteristics of the element
Atom
Matter and its properties are viewed on what level?
Atomic
Is an atom an element or compound?
Element
Is a molecule an element or compound?
Compound
Collection of atoms chemically bonded together in characteristic proportions
Molecule
A notation for representing elements and compounds; consists of the symbols of the constituent elements and subscripts identifying the # of atoms of each element in one molecule
Chemical formula
What is an example of a chemical formula?
H2O
Notation in which chemical formulas express the identities and their coefficients express the quantities of substances involved in a chemical reaction
Chemical equation
Energy that holds two atoms in a molecule together
Chemical bond
Ball and stick models
- Use spheres to represent atoms and sticks to represent chemical bonds
- Show correct angles but not size and distance
Space filling models
Use spheres to scale next to each other, more accurate but hard to see angles
A process for separating particles suspended in a liquid or a gas from that liquid or gas by passing the mixture through a medium that retains the particles
Filtration
Separates dissolved pigments/mixtures of compounds
Thin layer chromatography
A separation technique in which the more volatile (easily vaporized) components of a mixture are vaporized and then condensed, thereby separating them from the less volatile components
Distillation
An approach to acquiring knowledge based on observation of phenomena, development of a testable hypothesis, and additional experiments that test the validity of the hypothesis
Scientific method
A tentative and testable explanation for an observation or a series of observations
Hypothesis
General explanation of a widely observed phenomenon that has been extensively tested and validated
Scientific theory
E = mc^2
Energy, equivalent mass of matter, speed of light
Big Bang
All matter in universe approaches same point at same time
What is an example of serendipity?
Polytetrafluroetlene leads to finding of Teflon
Ability of making fortunate and unexpected discoveries by accident
Serendipity
Large chain like molecule built from many small molecules
Polymer
Study of matter and its transformations
Chemistry
Anything that occupies space and has mass
Matter
Substances composed of one type of atom
Elements
A property that is independent of the amount of substance present
Intensive property
A property that varies with the quantity of the substance present
Extensive property
A property of a substance that can be observed without changing it into another substance
Physical property
The ratio of the mass of an object to its volume
Density
Elements found in nature up combined with other elements
Free elements
A property of a substance that can be observed only by reacting it to form another substance
Chemical property
Has a definite volume and shape
Solid
Has a definite volume but not a definite shape
Liquid
Has neither a definite volume nor a definite shape
Gas
Matter changes from one state to another when energy is either (blank) or (blank)
Added or removed
Does it require more energy to melt a gram of ice at its melting point or to boil a gram of water that has been already heated to its boiling point?
Boil a gram of water that has already been heated to its boiling point
Transformation of a solid directly into a vapor
Sublimation
Transformation of a vapor (gas) directly into a solid
Deposition
The standard unit of length, named after the Greek Merton, which means “measure”
Meter
All the certain digits in a measured value plus one estimated digit
Significant figures
The extent to which repeated measurements of the same variable agree
Precision
Agreement between an experimental value and the true value
Accuracy
A fraction in which the numerator is equivalent to the denominator but is expressed in different units, making the value of the faction one
Conversion factor
The zero point on the kelvin temperature scale; theoretically the lowest temperature possible
Absolute zero
Smallest particle of an element that retains the characteristic chemical properties of that element
Atom
Can change near the atomic scale, however, as shown by recent advances in nanotechnology
Physical properties
A pure substance composed of two or more elements
Chemical compound
Can be observed and measure without changing the composition of a substance
Physical properties
Depend on the amount of substance present
Extensive properties
Do not depend on the amount present
Intensive properties
Identity of the substance is preserved
Physical changes
Substance is transformed into one or more substances
Chemical changes
Rigid, have fixed volumes and shapes
Solids
Definitive volume but no fixed shape
Liquids
No fixed volume or shape
Gas
Theory especially useful for describing and understanding physical states of matter
Kinetic molecular theory
The volume of a given substance decreases with (blank) temperature
Decreasing
Method of converting from one system of units to another
Dimensional analysis
Measurement has an equal probability of being high or low
Random error
Error that occurs in the same direction each time
Systematic error
