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 72.3

2. zeros between numbers are always significant 60.5

3. all final zeros to the right of a decimal place are significant 6.20

4. zeros that act as a placeholder are not significant 0.0253 & 4320

 

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