# Vocab – Chemistry Flashcard

 CHEMISTRY
 the study of matter and the changes that it undergos
 MATTER
 anything that has mass and takes up space
 MASS
 a measurement that reflects the amount of matter  the amount of matter that an object possesses
 WEIGHT
 a measure of the gravitational force exerted on an object
 SCIENTIFIC METHOD
 a systematic approach used in scientific study
 QUALITIVE DATA
 information that describes color, odor, shape, or some other physical characteristic  data that describes the physical properties
 QUANTITIVE DATA
 data that can be measured;  examples include SI units-measurement, accuracy, and percision.
 HYPOTHESIS
 a tentative explanation for what has been observed, is followed by an experiment to find out why this happened
 EXPERIMENT
 a set of controlled observations that test the hypothesis
 INDEPENDENT VARIABLE
 the variable that you plan to change
 DEPENDENT VARIABLE
 the variable whose amount changes in response to a change in the independent variable
 CONTROL
 a standard for comparison  it is usually set at 0 or is completely unchanged, something that would be found in nature
 CONCLUSION
 a judgement based on the information obtained in the experiment, states whether hypothesis was correct or not
 MODEL
 a visual, verbal, and/or mathematical explanation of experimental data
 THEORY
 an explanation that has been supported by many, many experiments
 SCIENTIFIC LAW
 a relationship in nature that is supported by many experiments but there is no explanation for why it happens
 SI UNIT
 units that are used in every country except for U.S.A.
 BASE UNIT
 a defined unit in a system of measurement that is based on an object or event in the physical world
 METER
 the SI unit for length, it is measured with a yard stick
 KILOGRAM
 the SI unit for mass, it is measured with a scale or triple-beam
 DERIVED UNIT
 a unit that is defined by a combination of base units ex: density=mass(g)/volume(l)
 LITER
 the SI unit for volume, is measured with water displacement for irregular shapes and geometry for regular shapes
 DENSITY
 the ration of mass to volume in an object;  the SI unit is g/cm3 (grams over cubic centimer);  the gram represents volume and the cubic cintimeter represents mass
 KELVIN
 the SI unit for temperature;  add 273 to convert Celcius to Kelvin and subtract 273 to convert K to C  measured with a thermometer
 SCIENTIFIC NOTATION
 writing a number so that it has only a tens place digitwise and will be multiplied to 10 with a power  ex1; 12300×10(-3)=12.3*3 is not being multiplied, it is used as an exponent  ex2; 9.2561327×10(4)=92561.327
 CONVERSION FACTOR
 a ratio of equivalent values used to express the same quantity in different units  changing kg to ml but not kg to l  ex; 203kg=203000g
 DIMENSIONAL ANALYSIS
 a method of problem solving that focuses on the units used to describe matter  to convert celcius to kelvin you focus on the relationship between the units
 ACCURACY
 how close a series of measured values are to to an accepted value or the true value
 PRECISION
 how close a series of measurements are to one another
 PERCENT ERROR
 the ratio of an error to an accepted value  the equation used to find this is percent error=(error/acceptedvalue) multiplied by 100
 Significant Figures
 the amount you have measured plus an extra digit  ex; if measured 2.3 and 2.4 and 2.2, you may actually have gotten 2.35 and 2.48 and 2.21 and the number of significant figures in the measures are all 3  the rules: (orange are significant)1. non zero #s are always significant 72.32. zeros between numbers are always significant 60.53. all final zeros to the right of a decimal place are significant 6.204. zeros that act as a placeholder are not significant 0.0253 & 4320

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