PUELLO
What test can you do to tell if dissolving sugar in water is a physical or chemical change?
Boil the solution
Which state of matter has particles that move past each other and take the shape of the container?
Liquid – particles move past each other and fill the container’s shape
Which is an example of a chemical change: rotting banana or breaking a rock?
Rotting banana is a chemical change
When water boils and bubbles form, is this a physical or chemical change?
Physical change – water changes state but not substance
How do you calculate the density of a block if you know its mass and volume?
Density = mass ÷ volume
When sugar dissolves in water, what happens to the sugar crystals?
Sugar crystals break apart into sugar molecules
What happens to the kinetic energy of molecules when ice melts into liquid water?
Molecules gain kinetic energy – water molecules move faster than ice molecules
Which is an example of a physical change: melting ice or grilling a hamburger?
Melting ice is a physical change
Which pizza-making step is a chemical change: kneading dough or baking the crust?
Baking the crust
Which property—mass, density, boiling point, or thermal conductivity—cannot identify a substance?
Mass – depends on amount, not identity
If sugar water is left to evaporate, what will remain in the beaker?
Solid sugar will remain after evaporation
Which images would correctly represent a gas: closely packed particles or widely spread ones?
Widely spread particles (not packed close)
What evidence during an experiment suggests a chemical change is taking place?
Bubbling, gas production, or new substance formed
How can a balance compare the densities of two liquids with the same volume?
The side that sinks lower has higher density
What type of change occurs when baking soda and vinegar produce bubbles?
Chemical change
Which property distinguishes liquids from solids in terms of shape?
Solids have definite shape; liquids do not
What physical property would NOT help classify two clear liquids—mass, boiling point, or density?
Mass – it depends on amount, not identity of substance
Why is burning a candle considered both a chemical and physical change?
Wax melting = physical change; burning = chemical change.
Does gravity affect density? Why or why not?
No, density does not depend on gravity because density measures MASS and not WEIGHT
Which state of matter has a definite volume but no definite shape?
Liquid – definite volume, no definite shape
Why is dissolving sugar in water considered a physical change, but burning sugar is a chemical change?
Dissolving sugar only changes physical state (no new substance). Burning sugar produces new substances (carbon + gases).
Explain why mass cannot be used to identify a substance, but density can.
Mass depends on the amount of material, but density is a unique ratio of mass to volume and helps identify substances.
Why does ice float in water even though both are made of the same substance?
Ice is less dense than liquid water because its molecules are more spread out in a crystal structure.
When making pizza, why is yeast fermentation a chemical change but kneading the dough only a physical change?
Fermentation produces new substances (gas + alcohol), making it chemical. Kneading only changes shape, so it’s physical.
How does removing gravity (such as in space) affect weight compared to mass?
Mass stays the same everywhere, but weight depends on gravity and would decrease in space.