Matter and Its Properties
What is matter?
Anything that has mass and takes up space.
What does mass measure?
The amount of matter in an object.
What is an atom?
A unit of an element.
A mixture looks the same throughout. Is it homogeneous or heterogeneous?
Homogeneous.
If a piece of paper is torn into smaller pieces, is that a physical or chemical change?
Physical change.
Is color a physical property or a chemical property?
Physical property
What does weight depend on?
Gravity
In the formula H₂O, how many hydrogen atoms are present?
2
Trail mix has visible pretzels, raisins, and cereal pieces. What type of mixture is it?
Heterogeneous.
Rust forms on a piece of iron. Is this a physical or chemical change?
Chemical change.
Which is a chemical property: conductivity, boiling point, color, or flammability?
Flammability
An object has a mass of 24 g and a volume of 8 mL. What is its density?
3 g/mL
How many total atoms are in CO₂?
3 atoms: 1 carbon and 2 oxygen.
Salt completely dissolves in water. Samples from the top, middle, and bottom contain the same amount of salt. What type of mixture is it?
Homogeneous.
Thermal energy naturally moves in which direction?
From warmer matter to cooler matter.
A metal is shiny, conducts electricity, and burns when placed in a flame. Which observation describes a chemical property?
Burning in a flame, because it describes the ability to form a new substance
A 12 kg object is moved from Earth to the Moon. Its mass stays 12 kg, but its weight decreases. Why?
Mass stays the same because no matter was added or removed, but weight decreases because the Moon has weaker gravity.
A model contains 2 nitrogen atoms and 6 hydrogen atoms. Which formula represents it?
N₂H₆
Oil and water form separate visible layers. What type of mixture is this, and why?
Heterogeneous because the substances are not evenly distributed and separate parts can be seen.
Two containers both contain water at 30°C. Container A has 200 mL and Container B has 500 mL. Which has more total thermal energy?
Container B, because it contains more water particles at the same temperature.
A student says, “Boiling point is a chemical property because the substance changes when it boils.” Is the student correct? Explain.
No. Boiling point is a physical property because boiling changes the state of the substance but does not create a new substance.
Three liquids form separate layers.
What is the order from top to bottom?
A, C, B.
A student says that O₂ is a compound because it contains two atoms. Is the student correct? Explain.
No. O₂ contains only one type of element, oxygen. A compound contains two or more different elements chemically bonded.
Student A says, “A homogeneous mixture is a pure substance because you cannot see different parts.” Student B says, “It is still a mixture even though it looks the same throughout.” Who is correct and why?
Student B. A homogeneous mixture still contains more than one substance physically combined, but the substances are evenly distributed.
A sealed container and everything inside it have a mass of 120 g before ice melts. After the ice melts, the total mass is still 120 g. Write a short CER explaining whether the amount of matter changed.
Claim: The amount of matter did not change.
Evidence: The total mass was 120 g before and 120 g after melting.
Reasoning: Matter is conserved during a physical change, so changing from solid ice to liquid water does not create or destroy matter.