States of Matter
Which state of matter has a definite shape and volume?
Solid
What is mass? What tool is used to measure mass?
The amount of matter in an object. A triple-beam balance.
A rock has a mass of 500 grams and a volume of 250 cm³. What is its density?
500 ÷ 250 = 2 g/cm³
What is the formula for density?
D=M/V
Give two examples of sample-size dependent properties.
Mass, volume, weight, size, length
How do the particles in a liquid move compared to those in a gas?
Liquid particles move more freely than in a solid but stay close together, while gas particles move quickly and are far apart.
How can you find the volume of an irregularly shaped object?
Use water displacement — measure how much the water level rises in a graduated cylinder.
Why do helium balloons rise in air?
The gas inside (helium) is less dense than the surrounding air.
What is Solubility?
The ability of a substance (solute) to dissolve in another substance (solvent).
Why does sugar dissolve faster in hot tea than in iced tea?
Higher temperature increases particle movement, improving solubility — a physical property.
How does temperature affect the movement of particles in each state of matter?
When temperature increases, particles move faster; when it decreases, particles move slower.
If you move an object to the Moon, does its mass or weight change?
Its mass stays the same, but its weight decreases due to weaker gravity.
How can you tell if two liquids have different densities just by looking at them in a beaker?
The denser liquid will sink to the bottom; the less dense will float on top.
What is a sample-size dependent property?
A property that changes when the amount of matter changes (also called an extensive property).
A student melts ice and then refreezes it. Has the identity of the substance changed?
No — melting and freezing are physical changes.
What state of matter is lava as it flows from a volcano?
Liquid — molten rock that flows but has no fixed shape.
Which property of matter determines whether an object sinks or floats in water?
Density.
A student fills a graduated cylinder to 40 mL with water, drops in a metal object, and the water level rises to 65 mL. If the object’s mass is 125 g, what is its density?
Volume = 65 – 40 = 25 mL → 125 ÷ 25 = 5 g/mL
A student heats two cups of water (100 mL and 200 mL) to boiling. Which will boil at a higher temperature?
Both will boil at the same temperature — boiling point is size-independent.
Why can a magnet separate iron filings from sulfur?
Iron is magnetic — a physical property that sulfur does not have.
How does the strength of particle attraction differ between solids, liquids, and gases?
Strongest in solids, weaker in liquids, and weakest (almost none) in gases.
Two cubes are the same size. Cube A has a mass of 8 g, Cube B has a mass of 4 g. Which cube has greater density and why?
Cube A — it has twice the mass for the same volume.
Is density a sample size independent property or a sample size dependent property? Explain.
Density is a sample size independent property. It does not change if the amount of matter changes.
What is a sample-size independent property? Give three examples.
Boiling point, melting point, density, conductivity, solubility, magnetism.
What is the boiling point of a substance? How does that compare to its melting point?
Boiling point is the temperature at which a liquid changes to a gas (vapor). Melting point is the temperature at which a solid changes to a liquid.