Matter and States
What is matter?
Anything that has space and takes up mass
Density formula
D=mass/volume
What is an element?
Substance made of one type of atom
What is a mixture
two or more substances that are physically combined
What causes seasons?
Tilt of Earth’s axis +position in orbit
What is kinetic energy?
Energy of motion
Density of Water
1 g/mL
Where are nonmetals located?
Right side of periodic table
Difference between homogeneous vs heterogeneous
uniform (homogenous) vs non-uniform
Length of earth's rotation
24 hrs
How do particles behave in solids and gases?
solids--tightly packed & vibrate
gases--spread & fast
Would an object float if it is more or less dense than water
Less dense
List 4 properties of metal
Good conductors, shiny, malleable, ductile
What allows filtration to separate mixtures
particle size
Which affects tides more--sun or moon and why?
Moon, closer to the Earth
What happens to particles when temperature increases?
move faster and spread out
If mass and volume double, what happens to density
stays the same
What are metalloids?
Elements with properties of metals and nonmetals
What is a pure substance
one type of element or molecule (H20 is pure)
What is an equinox
Equal day and night
When a solid melts into a liquid, the temperature stays the same during the entire melting process. Explain why the temperature does not increase even though heat is continuously being added.
All the added heat goes into breaking the attractive forces between particles, not increasing their kinetic energy. The temperature only rises again after the solid has fully melted.
Two objects made of different substances have the same mass, but Object A sinks in water and Object B floats. Explain exactly what this tells you about the relative densities of Object A, Object B, and water.
Object A is more dense than water (it sinks), Object B is less dense than water (it floats), and therefore Object A is more dense than Object B.
Silicon is a metalloid. Explain why Silicon can be used in both metal-like jobs (such as conducting electricity) and non-metal-like jobs (such as acting as an insulator), using particle behavior and periodic table position.
Because metalloids like Silicon sit between metals and nonmetals and have intermediate electron behavior — they can conduct electricity under some conditions (like metals), but not always (like nonmetals). This tunable conductivity is why Silicon is used in semiconductors.
A student mixes sand, salt, and iron filings into a beaker of water. Explain step-by-step how to separate all three components, naming the physical property used in each step.
Use a magnet to remove iron filings (magnetism).
Filter the mixture to separate sand (particle size).
Evaporate the water to recover the dissolved salt (boiling point/solubility).
Explain why the Southern Hemisphere experiences summer at the exact same time the Northern Hemisphere experiences winter, even though both hemispheres are the same distance from the Sun.
Because the tilt of Earth’s axis determines how direct the Sun’s rays are. When the Northern Hemisphere is tilted away from the Sun, it receives less direct sunlight (winter), while the Southern Hemisphere is tilted toward the Sun and receives more direct energy (summer). Distance from the Sun is not the cause.