States of Matter
What are the three main states of matter?
Solid, Liquid, Gas
What is the formula for density?
Density = Mass ÷ Volume
Is melting ice a physical or chemical change?
Physical
What is a pure substance?
A substance made of only one kind of particle (element or compound)
What happens to the density of a substance if its volume increases but mass stays the same?
Density decreases
Which state of matter has a definite shape and volume?
Solid
If an object sinks in water, is it more or less dense than water?
More dense
What type of change happens when iron rusts?
Chemical
What is a mixture?
Two or more substances combined but not chemically bonded
Describe how particles move in a gas compared to a solid.
Gas: move freely and quickly; Solid: vibrate in place
Which state of matter takes the shape of its container but keeps the same volume?
Liquid
True or False: Two objects of different sizes can have the same density.
True
True or False: A physical change creates a new substance.
False
What is the difference between a homogeneous and a heterogeneous mixture?
Homogeneous = looks the same throughout; Heterogeneous = you can see different parts
When water boils and becomes steam, is that a physical or chemical change?
Physical
What happens to the particles of a substance when it is heated?
They move faster and spread apart
A rock has a mass of 60 g and a volume of 20 mL. What is its density?
3 g/mL
Name two signs that a chemical change may have occurred.
Color change, gas/bubbles, temperature change, odor, or precipitate
Salt water is an example of what type of mixture?
Homogeneous mixture (solution)
Which has more kinetic energy: ice or steam?
Steam
Name one change of state and describe what happens (example: melting, freezing).
Example: Melting — a solid turns into a liquid as it gains heat.
You have honey, oil, and water. Which will float on top? Which will sink?
Oil floats, honey sinks (honey = most dense, oil = least dense)
Baking a cake — physical or chemical? Explain.
Chemical – new substance forms with heat and gas bubbles
Classify: air, salad, gold, granite.
Air = homogeneous; Salad = heterogeneous; Gold = pure substance; Granite = heterogeneous
How could you separate a mixture of salt and sand?
Add water (salt dissolves), filter (sand stays), evaporate water (salt remains)