Vocabulary Vault
Anything that has mass and takes up space.
Matter
The state of matter in which particles are tightly packed in an orderly arrangement and only vibrate in place.
Solid
The phase change that occurs when liquid water cools down and turns into solid ice.
Freezing
Tearing a sheet of loose-leaf paper into shreds or melting an ice cube are examples of this category of change.
Physical change
If 45 grams of reactants react completely inside a sealed, closed container, this is the total mass of the contents after the reaction.
45 grams
A tiny piece or basic unit of matter.
Particle
The state of matter that has a definite volume but takes the shape of whatever container it is poured into.
Liquid
The phase change occurring when a gas cools and turns into a liquid, such as water droplets forming on the outside of a cold glass.
Condensation
Wood burning in a campfire to produce ash and smoke, or an iron nail turning reddish-brown from rust.
chemical reaction (or chemical change)
The type of experimental setup or container where produced gases can escape freely into the surrounding atmosphere.
open system (or open container)
A starting substance present at the beginning of a chemical reaction
Reactant
The state of matter whose particles move freely, are spread far apart, and expand to fill any available space.
Gas
The process in which a liquid transitions into a gas only at its surface, occurring at temperatures below the boiling point.
evaporation
Name two distinct observational signs that provide evidence a chemical reaction has taken place.
gas production (fizzing/bubbles), temperature change, unexpected color change, or precipitate (solid) formation
An open beaker reaction starts with an initial mass of 52.4 g and ends with a measured mass of 50.8 g. This is the difference in mass.
1.6 grams
A substance formed as a result of a chemical reaction.
Product
This happens to the speed and kinetic energy of particles when thermal energy (heat) is added to a substance.
they move faster (gain kinetic energy)
The key physical difference between evaporation and boiling.
evaporation happens only at the surface at any temperature, while boiling occurs throughout the liquid at a specific boiling point
The reason boiling water on a stove is classified as a physical change rather than a chemical reaction.
the water changes state from liquid to gas, but the molecules remain water (no new chemical substance is formed)
Where the missing mass went when an open beaker loses weight after a vigorous fizzing reaction.
it escaped into the surrounding air as a gas
The scientific principle stating that matter is neither created nor destroyed during a chemical reaction in a closed system.
Law of Conservation of Mass
The reason why gases do not have a fixed shape or a fixed volume compared to solids and liquids.
very weak attractions between particles allow them to move independently and spread out in all directions?
The phase change where a solid transforms directly into a gas without melting into a liquid first (such as dry ice).
sublimation
The scientific reason why seeing bubbles in a liquid is not 100% proof that a chemical reaction took place.
bubbles can be produced by physical changes, such as boiling or trapped air being released
Why a sealed, closed system is necessary to scientifically demonstrate the conservation of matter during a reaction that produces a gas.
it prevents gas products from escaping and outside air from entering, allowing all matter to remain on the balance to be measured