1
If water is in a pot and it is boiling, what 2 states of matter are present?
liquid (water in the pot)
gas (water vapor/steam rising from it)
___________________ are easy to compress
gases
Why does nitrogen at room temp boil but water does not?
What is different about them?
their types of atoms are different giving them different properties (different melting and boiling points)
The chemical formula for water is H₂O . What does this tell us about the make up of water mloecules?
The chemical formula H₂O tells us that each water molecule is made up of:
2 hydrogen (H) atoms
1 oxygen (O) atom
A _________________ is a substance made of only one type of atom.
element
Does a solid, liquid or gas have more potential energy? Why?
Particles in a gas, because they are farther apart.
_____________________ is a small piece of matter such as an atom or molecule
particle
What happens to particle motion and kinetic energy when a substance is heated?
partciles move faster, kinetic energy increases
A _________________________ has a definite shape and a definite volume
solid
_____________________ is the measure of the average kinetic energy of the particles.
temperature
Potential energy _______________________ as particles move farther apart (for example when solid becomes liquid or liquid becomes gas).
increases
True or False: A larger sample of water will change the ratio of hydrogen and oxygen atoms in the water molecules
Why?
False
Compounds have a fixed ratio of atoms. A larger sample just has more molecules, but every molecule in that large sample still only has a 2:1 ratio (2 hydrogen for every 1 oxygen)
Is temperature a direct measure of thermal energy? Why?
No
To find thermal energy, you need to consider:
Mass – more matter = more particles = more total energy.
Temperature – tells you the average kinetic energy of the particles. (KE)
Type of substance – different materials store energy differently (specific heat). (PE)
if one pot of water has 1kg of water at 50 degrees C and another pot has 5kg of water at 50 degrees C, which has the most thermal energy and why?
5kg of water has more TE because it has more water molecules, so it has more total thermal energy even though the temperature is the same.
A ________________ contains atoms of two or more different elements bonded in a fixed ratio.
compound
Compared to solids and liquids, gas particles behave:
very far apart, move at high speeds
What happens to particles at 0K?
absolute zero, particles would stop motion (no kinetic energy)
How do particles in solids move and how are they spaced?
vibrate in place, closely packed
True or False? Thermal energy can increase even if the average kinetic energy is constant.
True
bc potential energy could increase by changing phase
____________________ have a definte volume but no definite shape
liquid