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level: Terms

Questions and Answers List

level questions: Terms

Question	Answer
determines the quantity, dimensions, or extent of something	measurement
a definite quantity adapted to as a standard of measurement	unit
how close the measurement is to the "true" value	Accuracy
the degree to which the measurement is reproducable	Precision
a digit that is either reliably known or estimated	Significant digit
how many sig figs are in 1.23	3
how many sig figs are in 0.0012	2
how many sig figs are in 0.1100	4
how many sig figs are in 2500	2
how many sig figs are in 0.09030	4
how many sig figs are in 109.0	4
how many sig figs are in 0.00900	3
round this to 3 sig figs: 5345	5350
round this to 3 sig figs: 0.01457	0.0146
round this to 3 sig figs: 1.053	1.05
the comparison of the experimental measurement to its accepted value.	percent error
cannot be described in terms of anything else. ex: mass=kg, length=m, time=s	Fundamental measurement unit
fundamental measurements combined to make a derived unit. ex: speed=m/s, density=g/cm^3	Derived measurement unit
the study of matter and the changes it undergoes	chemistry
anything that has mass and occupies space	matter
the most basic form of matter (ex: silver, gold, copper)	element
composed of small indivisible particles called atoms	matter
composed of atoms and different elements combined in small whole-number ratios	chemical compounds
the rearrangement of atoms into different combinations	chemical reactions
smallest fundamental particle of an element that has the properties of that element	atom
the first particle discovered (JJ thompson 1897)	electron
electrons have a _______ charge	negative
+ in the nucleus	protons
0 in the nucleus	neutrons
- outside the nucleus	electrons
number of protons in the nucleus	atomic
protons + neutrons	mass number
atoms of the same element with differeing mass numbers	isotopes
substance composed of two or more elements that are chemically combined (water, table salt, sugar)	Compound
made up of atoms	Elements
a substance where the atoms are held together by covalent bonds, ex: H2O	molecular compounds
compounds consisting of ions (atoms who have gained either a positive or negative charge)	Ionic compounds
electrostatic forces holding the ions together	Ionic bonds
charged particle	Ion
positive charged particle	Cation
negative charged particle	anion
matter is neither created nor destroyed in chemical reactions	law of the conservation of mass
solids, liquids, gas	physical states
have definite composition and definite unchanging properties	pure substances
pure substances tendency to undergo chemical change. ex: burning, color changes, tarnishing	chemical properties
a substance exists in a particular physical state under defined conditions. increase in temp will alter physical state (ex: color, odor, taste)	physical properties
property that does not depend on the amount of material (ex: density)	intensive properties
property that does depend on the amount of material present (ex: mass, volume)	extensive property
when a substance is chemically converted to another substance.	chemical change
ratio of mass to volume - an intensive property	density
change in physical property (ex: melting, freezing)	physical change
non-uniform mixture containing two or more substances (ex: salt and pepper, oil and water)	heterogeneous mixture
uniform mixture, same throughout (ex: salt water, milk)	Homogeneous mixture
substance being dissolved	solute
substance doing dissolving	solvent
the capacity to do work	energy
energy cannot be created nor destroyed, but only transformed from one form to another	law of the conservation of energy
produce energy	exothermic reactions
require energy	endothermic reactions
energy availalbe due to position or composition	potential energy
energy resulting from motion	kinetic energy
amount of heat required to raise the temp of one gram of water from 14.5C to 15.5C	calorie (cal)
the amount of heat required to raise the temperature of one gram of a substance to one degree celsius (kelvin) - reflects how some substances heat up faster than others	specific heat