Praxis Middle School Science-Matter and Energy Flashcards
matter
makes up everything in the world
takes up space and has mass
mass
the measure of the amount of matter in an object
weight
the measure of earth’s pull of gravity on an object
also the pull of gravity between other bodies-the mass of an object remains the same but the weight changes depending on gravity.
volume
the amount of cubic space that an object occupies
density
the mass of a substance contained per unit volume
physical property
a characteristic that can be observed without changing the identity of a substance
chemical properties
describes the capacity of a substance to be changed into new substances
the stars manufactured
every chemical element heavier than hydrogen
the thing cloud (planetary nebula) of gas and dust, from which the sun and its planet formed, was struck by the shock waves and remnant matter from exploded stars outside of our galaxy
solar system
inner planets’ composition: reflects the sun’s attraction of the heavier elements
outer planets’ composition: reflects the lighter, less dense elements attracted less by the sun’s gravitational mass.
on each planet, heavier elements…
sink inward to form the core
lighter elements form the atmosphere
our planet’s earliest history…
violent.
struck by meteorites
the earth’s birthing process produced…
frequent eruptions that caused water to rise to the surface, and the solar system contributed to additional water to the primordial seas.
the percentage of sodium in the earth’s oceans has
not varied appreciably for at least 600 million years
earth’s core composed of
iron and nickel
earth’s crust is rich in
silica
atmosphere consists of
78% nitrogen and 21% oxygen
how many naturally occurring elements are their in the universe?
92
of the 92 naturally occurring elements…
only 8 make up 99% of earth’s mass.
physical change
does not create a new substance
does not rearrange atoms into different compounds
ex: bending a nail
chemical change
converts one substance into another by rearranging atoms to form a different compound
ex: iron oxide (rust) is present in a rusty nail
solid
matter that has definite shape and volume
liquid
matter that has definite volume, but no shape
gas
no shape or volume
spreads out to occupy entire space of whatever container it is in
energy
the ability to cause change in matter
evaporation
the process of changing a liquid to a gas
condensation
the process of changing a gas to a liquid
composition reaction
two or more substances combine to form a compound
decomposition reaction
a compound breaks down into two or more simpler substances
single replacement reaction
decomposition reaction; a compound breaks down into two or more simpler substances
double replacement reaction
parts of two compounds replace each other, seeming to switch partners
principle of conservation of mass
the total mass of system is constant
when matter changes phase
mass remains constant
law of conservation of energy
matter is neither created or destroyed, but merely changes state
either giving off or absorbing energy in the process
joules
measurement of work as the product of force on an object and the distance through which the object is moved
thermal energy
the energy moving atoms and molecules
chemical energy
the energy that bonds atoms and molecules together
nuclear energy
energy of moving the nucleus of an atom
mechanical energy
energy of moving objects
potential energy
energy stored in an object due to its position
elastic potential energy
energy stored in elastic (stretchable) objects such as rubber bands or springs
gravitational potential energy
energy of an object has when it is in an elevated position
kinetic energy
energy of an object has due to its mass and motion
four states of matter
liquid solid gas plasma
plasma
a superheated, molten gas, and not all physicists or textbooks agree that it is a separate state of matter
