science chapter 2-3 short answer Flashcards
how do the properties of a compound compare to the properties of the elements it contains?
they are different
how is the composition of a substance different from the composition of a mixture?
comp. of a substance= fixed
comp. of a mixture= can vary
what is viscosity?
measure of a substances resistance
based on the information in figure 2-1, which substances would be gases at 0 degrees C
hydrogen, nitrogen
explain why boiling can be used to separate water from the other compounds in seawater
the water will evaporate and what is left will stay behind
what is flammability?
the ability of a substance to burn originate
is flammability a physical or chemical property? explain…
chemical its combustion is a chemical change
what kind of change is taking place if you see white mold growing on a strawberry?
chemical
what are 3 common clues that a chemical change has occurred?
giving off heat or light, change in color,production of gas , formation of precipitate
why does the air pressure in a cars tires increase after a long drive/
friction, the warmer it gets the higher the pressure
explain why boiling water in a large pot on a stove has a temp. of 100 degrees C even if it has been boiling for an hour?
a phase change is taking place as the water boils and changes from a liquid to a water vapor (the temp,. does not change)
describe what happens to the arrangement of water molecules as ice melts…
at the melting point of water, some molecules gain enough energy to move from their fixed positions
describe what happens to the average kinetic energy of water molecules as water freezes…
as water freezes, it relates energy to its surroundings and the average kinetic energy of molecules decreases
name and describe the phase change that occurs when dry ice is placed in an open container at room temp.
at room temp. dry ice changes from a solid carbon dioxide gas, (sublimation)
what factors affect the volume of a weather balloon as it rises through the atmosphere?
temperature, air pressure
