S6 - Q4 - Unit 1 Review
Matter and Its Interactions + Critical Thinking
Learning Objectives
Apply knowledge of intensive and extensive properties, including density calculations, to identify substances and solve problems
Explain states of matter, phase changes, and heating curves using kinetic molecular theory
Compare conduction, convection, and radiation, and distinguish conductors from insulators
Identify the 8 logical fallacies by name and definition
Detect logical fallacies in real-world scenarios
Apply the 3-question defense strategy to evaluate claims
Properties of Matter Review
~5 minutesProperties of Matter
All matter has properties that help us describe and identify it. Properties fall into two categories:
Intensive Properties (DO NOT change with amount)
Intensive properties stay the same no matter how much of the substance you have. They are used to identify unknown substances.
- Density - mass per unit volume (d = m/V)
• Melting point - temperature at which a solid becomes a liquid
• Boiling point - temperature at which a liquid becomes a gas
• Solubility - how much solute dissolves in a solvent
• Color - the appearance of the substance
• Hardness - resistance to scratching
A wooden toothpick and a wooden log have the same density because they are made of the same material. The amount does not matter.
Extensive Properties (DO change with amount)
Extensive properties depend on how much matter is present.
- Mass - the amount of matter
• Volume - the space matter occupies
• Weight - the gravitational force on an object
• Length - a measure of distance
Density
Formula: d = m / V
Units: g/mL or g/cm3 (these are equivalent for liquids)
Float/Sink Rule:
• Density less than 1.0 g/mL = floats in water
• Density greater than 1.0 g/mL = sinks in water
Example calculation: An object has a mass of 24 g and a volume of 8 mL.
d = m / V = 24 g / 8 mL = 3.0 g/mL
Since 3.0 > 1.0, this object sinks in water.
Intensive properties do NOT change with the amount of matter. Examples: density, melting point, boiling point, solubility, color, hardness. Used to IDENTIFY substances.
Extensive properties DO change with the amount of matter. Examples: mass, volume, weight, length. Cannot be used to identify a substance on their own.
Properties of Matter Practice
Which of the following is an intensive property?
A wooden log and a wooden toothpick have different densities because the log is much larger.
The formula for density is d = {blank1} / {blank2}.
A scientist measures the boiling point of a small beaker of liquid and gets 78 degrees Celsius. She then repeats the experiment using a much larger container of the same liquid. What boiling point will she record?
An object has a mass of 45 g and a volume of 15 mL. What is its density?
An object with a density of 0.8 g/mL will sink in water.
Which of the following are intensive properties? (Select all that apply)
Select all that apply.
A block of metal has a mass of 156 g and a volume of 20 cm3. Will it float or sink in water?
Two unknown liquids are tested. Liquid A has a density of 1.26 g/mL and Liquid B has a density of 0.79 g/mL. If they are poured into the same container and do not mix, which liquid will be on top?
A mystery substance has a mass of 36 g and a volume of 4 mL. Its density is {blank1} g/mL. This substance will {blank2} in water.
States of Matter and Phase Changes Review
~5 minutesStates of Matter and Phase Changes
Kinetic Molecular Theory
All matter is made of tiny particles (atoms or molecules) that are in constant motion. Temperature measures the average kinetic energy of the particles. Higher temperature = faster particle motion.
Three States of Matter
| State | Shape | Volume | Particle Behavior |
|---|---|---|---|
| Solid | Fixed shape | Fixed volume | Particles vibrate in fixed positions |
| Liquid | Takes container shape | Fixed volume | Particles slide past each other |
| Gas | Fills entire container | Fills entire container | Particles move freely and rapidly |
Six Phase Changes
Energy ADDED (particles speed up):
• Melting - solid to liquid
• Evaporation/Boiling - liquid to gas
• Sublimation - solid directly to gas
Energy REMOVED (particles slow down):
• Freezing - liquid to solid
• Condensation - gas to liquid
• Deposition - gas directly to solid
What Happens During a Phase Change?
During a phase change, the temperature stays CONSTANT. This appears as a flat horizontal line on a heating curve. The energy being added (or removed) goes into breaking or forming bonds between particles, not into raising or lowering the temperature.
Heating Curve (from solid to gas)
1. Temperature rises as solid warms up 2. Temperature plateaus at the melting point (solid melts to liquid) 3. Temperature rises as liquid warms up 4. Temperature plateaus at the boiling point (liquid boils to gas) 5. Temperature rises as gas warms up
Energy ADDED: melting, evaporation, sublimation (particles break free)
Energy REMOVED: freezing, condensation, deposition (particles lock together)
Temperature stays CONSTANT during ALL phase changes. The energy goes into changing the arrangement of particles, not into changing the temperature.
States and Phase Changes Practice
According to the Kinetic Molecular Theory, temperature is a measure of:
Match each phase change to its description.
During a phase change, the temperature of a substance continues to increase as energy is added.
Which phase change occurs when energy is REMOVED from a gas?
A beaker of ice at -10 degrees Celsius is placed on a hot plate. Arrange the events in order as energy is continuously added.
Which phase changes require energy to be ADDED? (Select all that apply)
Select all that apply.
In which state of matter do particles vibrate in fixed positions?
The phase change from liquid to solid is called {blank1}, and it occurs when energy is {blank2} from the substance.
On a heating curve, a flat horizontal line represents:
Sublimation is the phase change from a liquid directly to a gas.
Energy Transfer Review
~5 minutesEnergy Transfer
Thermal energy always flows from WARMER objects to COOLER objects until both reach the same temperature. This is called thermal equilibrium.
Three Methods of Heat Transfer
| Method | How It Works | Where It Works | Example |
|---|---|---|---|
| Conduction | Direct contact between particles. Particles collide and transfer energy. | Best in solids, especially metals | Touching a hot stove burns your hand |
| Convection | Fluid circulation. Warm fluid rises, cool fluid sinks, creating currents. | Liquids and gases only | A pot of boiling water circulates |
| Radiation | Electromagnetic waves. No particles or medium needed. | Works through empty space | The Sun heats the Earth across space |
Key Details
- Conduction works best in metals because their particles are tightly packed and electrons move freely.
• Convection creates currents: warm fluid rises (less dense), cool fluid sinks (more dense), and the cycle repeats.
• Radiation is the only method that works through empty space (vacuum). This is how the Sun's heat reaches Earth.
Conductors vs. Insulators
- Conductors transfer heat easily: copper, aluminum, iron, steel, and other metals
• Insulators resist heat flow: wood, plastic, rubber, air, wool, foam, glass
Conductors are used in cooking pans to transfer heat quickly. Insulators are used in oven mitts and winter coats to slow heat transfer.
Thermal equilibrium - when two objects reach the same temperature and heat transfer stops
Conduction - heat transfer through direct contact between particles
Convection - heat transfer through circulation of fluids (liquids or gases)
Radiation - heat transfer through electromagnetic waves, works through empty space
Conductor - a material that transfers heat easily (metals)
Insulator - a material that resists heat flow (wood, plastic, rubber, air)
Energy Transfer Practice
Which method of heat transfer requires direct contact between particles?
How does the Sun's heat reach Earth?
Match each example to its heat transfer method.
Thermal energy flows from cooler objects to warmer objects.
Which of the following are good conductors of heat? (Select all that apply)
Select all that apply.
In convection, warm fluid _____ and cool fluid _____.
When two objects reach the same temperature, they have reached thermal {blank1}.
A student wraps a hot potato in aluminum foil and then in a thick cloth. The foil transfers heat quickly to the cloth because foil is a good _____. The cloth slows heat loss to the air because cloth is a good _____.
Critical Thinking Review
~3 minutesLogical Fallacies Quick Reference
A logical fallacy is an error in reasoning that weakens an argument. Learn to recognize these 8 common fallacies:
| Fallacy | What It Does | Example |
|---|---|---|
| Ad Hominem | Attacks the person, not the argument | "You failed math, so your opinion on the budget is worthless." |
| Straw Man | Distorts the argument into an extreme version | "You want less homework? So you want students to never learn anything?" |
| Red Herring | Changes the subject to distract | "Why worry about pollution when there are potholes on the roads?" |
| Bandwagon | Claims something is true because everyone does it | "Everyone is buying this phone, so it must be the best." |
| False Dilemma | Presents only two options when more exist | "Either you agree with me, or you don't care about the environment." |
| Slippery Slope | Claims one step leads to disaster without evidence | "If we allow phones in class, students will never read books again." |
| Appeal to Authority | Uses a famous person without relevant expertise | "This celebrity says the product works, so it must." |
When you hear a claim, defend yourself against faulty reasoning by asking three questions in order:
1. What is the actual claim? - Identify exactly what is being argued. 2. What evidence supports it? - Look for facts, data, or logical reasoning. 3. Is the reasoning valid, or does it contain a fallacy? - Check for any of the 8 fallacies.
If the claim fails any of these questions, it may not be trustworthy.
Critical Thinking Practice
Which logical fallacy attacks the person making the argument instead of addressing the argument itself?
Match each statement to the logical fallacy it demonstrates.
A student says: "You want to ban plastic straws? Next you'll want to ban all plastic, and then we'll be living in caves!" Which fallacy is this?
"A famous basketball player says this energy drink is healthy, so it must be good for you." Which fallacy is this?
"This is the best restaurant in town because no restaurant here is better." Which fallacy is this?
A friend says: "Why are you worried about your grade in science? There are kids starving in other countries." Which fallacy is this?
What is the FIRST question you should ask when evaluating a claim using the 3-question defense?