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chem_ch1
chem_test1
| Question | Answer |
|---|---|
| the process of studying natural phenomena, involving observations, forming laws. and theories, and testing of theories by experimentation | scientific method |
| quantitative observation that has a number and a scale | measurement |
| one or more assumptions put forth to explain the observed behavior of nature | hypothesis |
| a set of assumptions put forth to explain some aspect of the observed behavior of matter | theory |
| (theory) a set of assumptions put forth to explain the observed behavior of matter. The models of chemistry usually involve assumptions about the behavior of individual atoms or molecules. | model |
| a statement that expresses generally observed behavior | natural law |
| mass is neither created nor destroyed | law of conservation of mass |
| international system of units based on the metric system and units derived from the metric system | SI system |
| the quantity of matter in an object | mass |
| the force exerted on an object by gravity | weight |
| (in measurement) the characteristic that any measurement involves estimated and cannot be exactly reproduced | uncertainty |
| the certain digits and the first uncertain digit of a measurement | significant figure |
| the agreement of a particular value with the true value | accuracy |
| the degree of agreement among several measurements of the same quantity; the reproducibility of a measurement | precision |
| an error that has an equal probability of being high or low | random error |
| an error that always occurs in the same direction | systematic error |
| expresses a number N x 10^m, a convenient method for representing a very large or very small number and for easily indicating the number of significant figures | exponential notation |
| an equivalence statement between units used for converting from 1 unit to another | unit factor method |
| unit factor method | dimensional analysis |
| a property of matter representing the mass per unit volume | density |
| the material of the universe | matter |
| the three different forms in which matter can exist; solid, liquid, and gas | states (of matter) |
| having visibly indistinguishable parts | homogeneous mixture |
| having visibly distinguishable parts | heterogeneous mixture |
| a homogeneous mixture | solution |
| a substance with constant composition | pure substance |
| a change in the form of a substance, but not in its chemical composition; chemical bonds are not broken in a physical change | physical change |
| a method for separating the components of a liquid mixture that depends on differences in the ease of vaporization of the components | distillation |
| a method for separating the components of a mixture containing and a liquid | filtration |
| the general name for a series of methods for separating mixtures by employing a system with a mobile phase and a stationary phase | chromatography |
| employs a strip of porous paper, such, as filter paper, for the stationary phase | paper chromatography |
| a substance with constant composition that can be broken down into elements by chemical processes | compound |
| the change of substances through a reorganization of the atoms; a chemical reaction | chemical change |
| a substance that cannot be decomposed into a simpler substances by chemical or physical means | element |
| a sequence of observations made under controlled conditions | experiment |
| information we gather using our senses, sight, taste, hearing, touch, smell | observation |
| measurements | quantitative |
| describes without using numbers | qualitative |
| measurements always consist of 2 parts: | a number and a scale |
| a place where experiments are conducted | laboratory |
| a very useful way to solve problems | scientific method |
| the first fundamental step of the scientific method | making observations |
| the second fundamental step of the scientific method | formulating hypothesis |
| the third fundamental step of the scientific method | performing experiments to test the hypothesis (key to the scientific method) |
| a possible explanation for an observation | hypothesis |
| is often called a model | theory |
| is a set of tested hypothesizes that give an overall explanation of natural phenomenon | theory |
| an attempt to explain why something happens | theory |
| gives us a mental picture which explains natural phenomenon | theory |
| a concise statement or equation that summarizes observed behavior | scientific law |
| people who use the scientific method to solve problems are called | scientists |
| try to better understand things even inf their discoveries cannot be put to immediate use | pure scientists |
| work is called pure science | pure scientists |
| put their scientific discoveries to work | applied scientists (engineers) |
| their work is called applied science or technology | applied scientists (engineers) |
| why must scientists continue to do experiments? | to refine our theories and laws. sometimes theories and laws are thrown out when they are not consistent with new data |
| one of the main branches of science | chemistry |
| the study of the structures, properties, composition, and changes of matter | chemistry |
| has been around for thousands of years | chemistry |
| shorthand method of writing very large and very small numbers | scientific notations |
| something that can be measured | quantity |
| a comparison between the quantity and a certain quantity called a unit of measurement | measurement |
| scientists use this set of units | SI |
| based on the metric system | SI |
| easier to use than the English system of units | SI |
| has 7 fundamental base units | SI |
| kilogram | kg length |
| second | s time |
| Kelvin | K temperature |
| Ampere | A electric current |
| Mole | mol amount of substances |
| SI unit for energy | 1J = 1m^2kg/s^2 |
| 1 L = | 1dm^3=1000cm^3=1000mL |
| mega | M 10^6 |
| kilo | k 10^3 |
| hecto | h 10^2 |
| deka | Da 10^1 |
| deci | d 10^-1 |
| centi | c 10^-2 |
| milli | m 10^-3 |
| micro | upside down u 10^-6 |
| nano | n 10^-9 |
| a measure of the quantity of matter (protons, neutrons, and electrons) in an object | mass |
| the force of attraction between a given mass and the earth | weight |
| uncertainty of a measurement is expressed by | accuracy and precision |
| refers to how close a measurement is to the accepted or true value | accuracy |
| refers to how close a series of measurements of the same thing are to each other | precision |
| tells how reproducible the measurements are | precision |
| means that a measurement has an equal probability of being high or low | random error |
| occurs in the same direction each time | systematic error |
| are the digits in a measurement that are known with certainty plus one that is uncertain (the digit furthest to the right is the uncertain or estimated digit) | significant figures |
| method used to convert from 1 unit to another | dimensional analysis/ unit factor method/ conversion factor method |
| are ratios having this form #unit/#unit | conversion factors |
| they equal one | conversion factors |
| are used to convert from 1 unit to another unit | conversion factors |
| come from equalities that state a relationship between 2 units | conversion factors |
| Freezing point of water = 0 | C |
| boiling point of water = 100 | C |
| used in chemistry experiments | C |
| used in chemistry calculations | K |
| freezing point of water = 273.15 | K |
| boiling point of water = 373.15 | K |
| used in engineering sciences | F |
| freezing point of water = 32 | F |
| boiling point of water = 212 | F |
| is the mass of substance per unit volume of substance | density |
| depends on temperature | density |
| used to identify a substance | density |
| d= ? m and v are given | d=m/v |
| m=? d and v are given | m=dv |
| v=? d and m are given | v=m/d |
| used to determine the volume of objects having irregular shapes | water displacement method |
| is anything that has mass and occupies space | matter |
| is a measure of the amount of matter in an object | mass |
| not affected by temperature or location | mass |
| 3 states of matter | solid, liquid, gas |
| rigid; has a fixed volume and shape and is slightly compressible | solid |
| has a fixed volume, but no fixed shape and is slightly compressible | liquid |
| has no fixed volume or shape and is easily compressible | gas |
| all matter can be classified into two groups | substances and mixtures |
| is matter that has a constant composition | substance |
| are substances which cannot be broken down into simpler substances by chemical or physical means | elements |
| 115 are known to exist | elements |
| 91 can be found in nature | elements |
| substance that can be broken down into simpler substances by chemical processes | compound |
| elements making them up are combined in a definite proportion by mass | compound |
| have different chemical and physical properties than the elements that make them up | compound |
| consists of 2 or more substances each of which retains its individual properties | mixture |
| substances that are combined to form a mixture are called | constituents or components |
| mixtures can be separated by physical means such as | distillation, filtration, and chromatography |
| composition can vary | mixture |
| a mixture of pure substances that has visibly indistinguishable parts | homogeneous mixtures/ solutions |
| a mixture of pure substances that has visibly distinguishable parts | heterogeneous mixture |
| a change in the form of a substance | physical change |
| no new substance is formed | physical change |
| a new substance is formed with different properties and a different formula (composition) | chemical change |
| following words usually signify a chemical change | burn, rot, rust, decomposed, ferment, explode, and corrode |