States of Matter
Which state of matter is the HOTTEST?
Gas
What is it called when a solid becomes a liquid? When a liquid becomes a solid?
I need both words!
solid -> liquid: melting
liquid -> solid: freezing
What instrument/tool do we use to measure mass?
Balance/ triple beam balance
The smallest unit of matter
Atom
Write the formula for density.
D= m/v = mass/ volume
Which state of matter is the most compact?
Solid
Do particles GAIN or LOSE energy when melting?
GAIN energy
because hotter temperature, move faster, breaking bonds/attractions between particles
What tool do we use to measure weight?
Scale
The types of atoms-- the different names on the periodic table
Example: something off the periodic table
A sample has a mass of 30.0g and a volume of 12mL. Calculate its density.
2.5 g/mL
What is special about the particles in a GAS that lets it change its volume?
The particles are all free to move and bounce around-- there is no set amount of space between each particle, it can easily change.
Do particles GAIN or LOSE energy during condensation?
Lose/release energy,
because the temperature decreases, or particles move slower
Name two ways to measure volume and state when you would use each.
"Normal shapes": ruler and math
Odd/irregular shapes: Graduated cylinder & ruler
What is the difference between a compound and a molecule?
Molecules are ANY 2 atoms bonded together
Compounds specifically have two DIFFERENT atoms bonded together
An object is measured to be 50 cm3 and 250 grams. What is its density?
D= m/v= 250/50 = 5 g/cm3
Draw the particles in a solid, then describe how they move.
Particles are all close together, students respond that they stay in place but vibrate/shake
Why does temperature stay constant during a phase change?
The thermal energy (that normally makes it hotter) is being used to break the bonds/attraction between particles
What is the difference between mass and weight?
Mass: how much matter
Weight: how much GRAVITY pulls on that matter
What is the difference between a compound and a mixture? Give an example of each.
Compound: different atoms BONDED together
Mixture: different PARTICLES, not bonded together
Liquid A has a density of 1.28 g/mL and
Liquid B has a density of 0.86 g/mL.
If the liquids separate, which will sit on top? Why?
Liquid B, because it is less dense
(it's not heavy enough to push Liquid A out of the way)
What is special about the particles in a LIQUID that lets the liquid flow, but keeps volume stable?
The particles can move and slide over each other, but they are still very close to each other (still have attraction between particles)
Define sublimation and give a real-world example
Solid --> Gas
Dry ice, deodorant, some perfumes... those are the examples I gave in class
Astronauts attempt to measure a sample of moon rock while still in space. Should they measure its mass or weight? Why?
Mass, because it is constant everywhere.
Weight changes based on the amount of gravity (ie the moon has less gravity)
Describe whether the air we breathe is a mixture or a molecule.
"Air" is a mixture of molecules like O2, N2, CO2, H2O, etc.
Humans need O2 gas when we breathe, but we inhale/exhale a variety of gases
What does density tell us about an object's particles?
It tells us how compact they are, how much space is between them.
ie A gas is less dense than a liquid because its particles have more space between them