Thermal Energy
This type of heat transfer occurs through direct contact between particles.
What is conduction?
Change from solid → liquid.
What is melting?
Negatively charged particle.
What is an electron?
Pure substance made of one type of atom.
What is an element?
Property that can be observed without changing identity.
What is a physical property?
This type of heat transfer occurs in fluids due to density differences.
What is convection?
Is melting endothermic or exothermic?
What is endothermic?
Particle located in the nucleus with no charge.
What is a neutron?
Two or more elements chemically bonded.
What is a compound?
Property that describes ability to form new substances.
What is a chemical property?
Heat transfer that does NOT require a medium.
What is radiation?
Identify ALL endothermic phase changes.
What are melting, vaporization, and sublimation?
What determines the identity of an element?
Number of protons.
Mixture where components are evenly distributed.
What is a homogeneous mixture?
Burning wood is what type of change?
What is a chemical change?
Explain why metal feels colder than wood at the same temperature.
Metal is a better conductor, so it transfers heat away from your hand faster.
Identify ALL exothermic phase changes.
What are freezing, condensation, and deposition?
Compare mass of proton vs electron.
Protons are much more massive than electrons.
Mixture where components are NOT evenly distributed.
What is a heterogeneous mixture?
Calculate density: mass = 40 g, volume = 10 mL.
What is 4 g/mL?
A pot of water is heated and currents form. Describe what happens to warm vs cool water.
Warm water rises (less dense), cool water sinks (more dense), creating convection currents.
A substance changes from gas → liquid.
a) Name the phase change
b) Is energy absorbed or released?
c) What happens to particle motion?
a) Condensation
b) Energy is released (exothermic)
c) Particle motion decreases as particles slow down and come closer together
If an atom has 12 protons and 13 neutrons, what is its mass number?
What is 25?
Salt dissolved in water — classify and justify.
Homogeneous mixture because it is uniform throughout.
A substance has density 0.8 g/mL. Will it float in water? Explain.
Yes, because it is less dense than water (1.0 g/mL).