The attraction of molecules at the surface of a liquid is called _______________.
surface tension
100
What is the scientific name for salt?
sodium chloride
100
The amount of a substance that can dissolve in a liquid at a particular temperature is called the __________________ of the substance.
solubility
100
Water and sand is an example of what kind of mixture?
a suspension
200
What kind of bond holds water molecules together?
covalent
200
Give an example of surface tension.
floating paperclip, water beading on penny, overfilling test tube
200
Explain how a salt crystal is put together.
Positive sodium ions are attracted to negative chlorine ions.
200
The substance being dissolved is called the ___________ and the substance doing the dissolving is called the _____________.
solute / solvent
200
A ______________ is a well mixed mixture.
solution
300
True or False: The valence electrons surrounding a water molecule are shared equally.
FALSE!
300
Explain why surface tension occurs.
Water molecules are pulled down and sideways (but not up) by other nearby polar molecules, creating a stronger surface.
300
Why can water easily dissolve salt?
The charged poles of the water molecules are attracted to the opposite charges of the sodium and chloride ions.
300
Whenever a solution forms, particles of the solute _______________________ and become surrounded by particles of the solvent.
leave each other
300
You misread the directions on the Crystal Light container and add 3 teaspoons instead of 3 Tablespoons. Your lemonade will be more ____________ than it's supposed to be.
diluted
400
When a neutral molecule has a positive area at one end and a negative area at the other, it is a ___________ molecule.
polar
400
Why doesn't alcohol behave in the same way as water when dropped onto a penny?
It's not very polar.
400
Why doesn't oil dissolve salt?
Oil is non-polar.
400
What are two factors that affect the solubility of a substance?
temperature, type of solvent
400
If I can continue to add sugar to my coffee and it dissolves easily, my solution must be __________________.
unsaturated
500
Explain where the charges are located on a water molecule AND how they join together to form a droplet.
oxygen = negative, hydrogens = positive
Opposite poles attracted
500
Explain why adding a bit of soap to the bead on the penny causes it to break apart and spill off.
The surface tension is interrupted by the polar ends of the soap molecules. The water droplet can no longer hold together.
500
Compare how temperature affects the solubility of salt vs. sugar.
An increase in temperature causes greater solubility in sugar, however the solubility of salt remains fairly constant, regardless of temperature.
500
Explain how solutes affect the freezing and boiling points of their solvents. Give an example of when this is helpful.
Solutes raise the boiling points and lower the freezing points. Anti-freeze does both.
500
What happens when you drop an ice cube into a saturated solution of saltwater? Explain why.
Some of the salt will fall out of the solution because the higher the temperature, the more solute can be dissolved.