Create an account
Which of the following statements about ice melting is true?
water molecules move from their fixed positions
the phase change in which a substance change from a solid to a gas or vapor without changing to a liquid first is
the Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided
what can you assume has happened if an electron moves to a higher energy level?
the electron has gained energy
which statement accurately represents the arrangement of electrons in Bohr's atomic model
electrons travel around the nucleus in fixed energy levels with energies that vary from level to level
which statement about electrons and atomic orbitals is true?
an electron cloud represents all the orbitals in an atom
the glowing of a neon light is caused by electrons emitting energy as they
move from higher to lower energy levels
which statement is true about the metalloid silicon
silicon is a better conductor of an electric current than sulfur is
among the alkali metals, the tendency to react with other substances
increases from top to bottom within the group
which of the following statements correctly describes the substance with the formula KI
there is a one-to-one ratio of potassium ions to iodide ions
in the compound MgCl2, the subscript 2 indicates that
there are two chloride ions for each magnesium ion
the water molecule H2O is polar because it contains two polar single bonds and
its molecule has a bent shape
water has a higher boiling point than expected because
of the strong attractions between polar water molecules
beryllium, Be, and chlorine, Cl, form a binary ionic compound with a one-to-two ratio of beryllium ions to chloride ions. the formula is
a force acting on an object does no work if
the force is not in the direction of the object's motion
a mechanical device requires 400J of work to do 340J of work in lifting a crate. What is the efficiency of the device?
an inclined plane reduces the effort force by
increasing the distance over which the force is applied
the ideal mechanical advantage of a pulley system is equal to the
number of rope segments supporting the load
in a ________ mixture, the parts of the mixture are noticeably different from one another
_____ is a process that could be used to separate dissolved particles from the liquid in a solution
when a metal changes color because it has reacted with another substance, a _______ change occurred
______ between particles of a gas and the walls of the container cause pressure in a closed container of gas
a graph representing Charles's law shows that the _______ of a gas increases at the same rate as the ______ of the gas
when all the electrons in an atom are in orbitals with the lowest possible energy, the atom is in its ______ state
Mendelev's periodic table was useful because it enabled scientists to predict properties of unknown ______
from left to right across a period in the periodic table, elements become less _____ and more ________ in their properties
in general, a _______ metal will be more reactive than an alkaline earth metal in the same period
the two most reactive groups of elements in the periodic table are the alkali metals and the ________
any part of a force that does not act in the direction of an object's motion does no _____ on an object
you calculate work by multiplying the force acting in the direction of _______ by the distance the object moves
a substance has a melting point of 0C and a boiling point of 100C. the substance is most likely
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together