States of Matter
Which state of matter has particles that vibrate in place while staying tightly packed together?
Solid
What change of state occurs when water vapor cools and becomes liquid water?
Condensation
Which physical property describes how easily a substance dissolves in another substance?
Solubility
What is the difference between a mixture and a solution?
A mixture contains two or more substances combined physically. A solution is a mixture in which one substance dissolves evenly in another.
A piece of paper is torn into smaller pieces. Is this a physical or chemical change?
Physical change, the paper changes size and shape but remains paper.
A liquid is poured from a tall, narrow container into a short, wide container. What changes about the liquid, and what stays the same?
Its shape changes to match the new container, but the liquid itself remains a liquid.
When a solid melts, does it gain or lose energy? How does its particle movement change?
It gains energy, and its particles move faster and begin sliding past one another.
Object A has masses of 10 g, 15 g, and 8 g on one side of a balance. Object B has masses of 20 g, 7 g, and 12 g. Which object has the greater mass, and how much greater is it?
Object B has a mass of 39 g, while Object A has a mass of 33 g. Object B is 6 g heavier.
A student mixes sugar into water until the sugar is no longer visible. Which substance dissolved, and which substance did it dissolve in?
Sugar dissolved in water.
A metal gate develops rust after being exposed to air and moisture. Is this a physical or chemical change?
Chemical change, rust is a new substance.
Why can a gas spread throughout an entire container while a solid cannot?
Gas particles are far apart and move freely in all directions, while solid particles vibrate in fixed positions.
A wet sidewalk dries after the sun comes out. What change of state occurs, and what happens to the water particles?
Evaporation; the particles gain energy, move faster, and spread farther apart as they become a gas.
A student wants to determine whether an unknown object is magnetic. Which property should the student test?
Magnetism
A student mixes oil and water. After stirring, the oil forms a separate layer. Does this mixture form a solution? Why or why not?
No. The oil and water separate instead of mixing evenly into a solution.
A student melts a piece of chocolate and then lets it harden again. Is this a physical or chemical change? Explain.
A physical change, because the chocolate changes state but no new substance is formed.
A student draws particles that are close together but arranged randomly, with arrows showing movement past one another. Which state of matter is shown?
Liquid
How are freezing and melting different in terms of energy and particle movement?
During melting, particles gain energy and move faster. During freezing, particles lose energy and move more slowly.
An unknown object is hard, silver-colored, and attracted to a magnet. Name two physical properties that could help identify it.
hardness, color, or magnetism
Salt and sand are each mixed with water in separate cups. The salt dissolves, but the sand settles to the bottom. What does this tell you about their solubility?
Salt is soluble in water, while sand is not readily soluble in water.
An egg is cooked in a frying pan. Is this a physical or chemical change? Explain your reasoning.
A chemical change, because cooking produces changes in the egg that form new substances with different properties.
A substance has a definite shape, and its particles are tightly packed but still moving slightly. What is the substance's state of matter, and how are its particles moving?
Solid, its particles vibrate in place.
A student says, "When water freezes, its particles turn into different particles." Explain why this statement is incorrect.
The particles remain the same. They lose energy, slow down, and become arranged in fixed positions as the water freezes.
A student says that two objects made from the same material must have the same mass. Is the student correct? Explain.
No. Objects made from the same material can have different masses if they contain different amounts of matter.
A student mixes salt and sand together. How could the student use water to separate the two substances, based on their solubility?
Add water so the salt dissolves while the sand remains undissolved. The sand can then be separated from the saltwater.
A student cuts a piece of paper and then burns another piece of paper. Explain why these changes are different types of changes.
Cutting paper is a physical change because the paper changes size and shape but remains paper. Burning paper is a chemical change because new substances form.