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Stack #64231
question | answer |
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Mass | Quntity of matter in a particular body. |
Weight | Measure of the gravitational force of attraction between the body's mass and the mass of the planet or satelite on which it is weighed. |
Volume | Cubic space taken up by matter. |
Temperature | Degree of hotness of matter. |
Density | Mass of a substance occupying a unit volume, expressed as the mass divided by the volume. |
Metric system | System of weights and measures in which each unit is a tenth, hundredth, thousandth, and so on, of another unit: it is the standard system in use in every nation except the United States and is used extensively by scientists. |
Mass | Quantity of matter in a particular body. |
Significant digits (figures) | Digits in a measurement that are known to be precise, along with a final digit about which there is some uncertainty. |
Exact numbers | Numbers for measurements that are precisely known and can have as many significant digits as a calculation requires, and so they are not used to determine the number of significant digits for an answer. |
Exponent | Whole number or symbol written as a superscript above a base and denoting the number of times the base is to be multiplied by itself. |
Exponential notation | Form of mathematical expression in which a number is expressed as the product of two numbers, one a decimal and the other a power of 10. |
Scientific notation | Form of exponential notation in which the decimal part must have exactly one nonzero digit to the left of the decimal point; it is widely used by scientists. |
Demensional analysis (factor unit method) | Method of converting among measures expressed in different units by developing a relationship between these units and expressing this relationship as a factor of both units. |
Specific gravity | Density of a substance divided by the density of some substance taken as a standard. |
Physical state | Any of three forms in which matter may exist, as a gas, as a liquid, or as a solid; the state depends on the surrounding temperature and atmospheric pressure, as well as on the secific charateristics of the particular type of matter. |
Heterogeneous matter | Matter that is not uniform in composition and/or properties throughout the sample, but rather consists of two or more distinct substances unequally distributed. |
Mixture | Heterogeneous matter composed of two or more pure substances, each of which retains its identity and specific properties. |
Hemogeneous mixture | Homogeneous throughout and composed of two or more pure substances whose proportions can be varied in some cases without limit. |
Solution | Homogeneous mixture involving two or more pure substances; its composition usually can be varied within certain limits. |
Pure substance | Substance characterized by definite and constant composition and having definite and constant properties under a given set of conditions. |
Compound | Any pure substance that can be broken down by chemical means into two or more different, simpler substances. |
Element | Any pure substance that cannot be broken down by ordinary chemical means into two or more different, simpler substances. |
Atom | Smallest piece of an element that can exist and still exhibit the propreties of that element including the ability to react with other atoms. |
Molecule | Smallest particle of a pure substance that can exist and undergo chemical changes. |
Law of difinite proportions (constant composition | Principle that a given pure compound always contains the same elements in exactly the same proportions by mass. |
Physical properties | Properties of a substance that can be observed without the composition of the substance changing. |
Chemmical properties | Properties of a substance that can be observed only when a substance undergoes a change in composition. |
Physical changes | All changes in a substance other than changes in its chemical compostition. |
Chemical changes | Changes that result in changes in the composition of the substance. New substancees are formed. |
Energy | Capicity to do work or transfer heat. |
Potential energy | Energy possessed by a substance by virtue of its position in space or its chemical composition. |
Kinetic energy | Energy possessed by a substance by virtue of its motion. |
Heat energy | Energy transferred from one substance to another when there is a temperature difference between the substances: it is associated with the random motion of molecules. |
Calorie (cal) | Standard unit for the measurement of heat energy; 1 cal is equal to the quantity of heat required to raise the temperature of 1g of wather from 14.5 to 15.5 C. |
Joule (J) | Standard unit for the mearsurement of heat energy in the Systeme International (SI); 4.184J = 1 cal. |
Specific heat | Joules of heat required to raise the temperature of 1.00 kg of a substance by 1.00 K or calories to raise the temperature of 1.00 g of a substance by 1.00 C. |