What is matter?
All matter is made up of extremely small particles called:
atoms
The three basic states of matter are:
solids, liquids, and gases
True or false: A physical property tells you the types of permanent changes that matter can undergo.
False! Physical properties are used to observe and describe characteristics of matter that are typically reversible.
If I roast a marshmallow with fire, is that a physical or chemical change?
Chemical change
Density is a ____________ property.
physical
How many known elements are there?
118 elements
A substance has atoms that slide past each other slowly. What state is the substance in?
Liquid
Name 3 physical properties that we've learned in class.
Answers could include density, solubility, volume, boiling point, melting point, freezing point, size, shape, 5 senses, etc.
If I get a hair cut and get it styled with curls, is that a physical or chemical change?
Physical change
All atoms of the same ____________ have the same properties.
element
All matter has ________ and __________.
mass and volume
When heat is removed, a liquid can become a
solid
Name 3 chemical properties we've learned in class.
Answers could include flammability, oxidation, toxicity, sensitivity to light, reactivity to water, rusting, etc.
Why is rusting a chemical change?
When iron reacts with oxygen in the presence of moisture, it forms a new substance called iron oxide (rust), which has different properties than the original iron. You will not have the same amount of metal even if you remove the rust.
True or false: All substances melt at the same temperature?
False! Different substance have different melting, boiling, and freezing points.
The theory of ____________ of matter states "matter cannot be created or destroyed".
conservation
When a solid becomes a gas and does not go through a liquid phase, that is called ______________.
Define density (what makes something dense?) What is the formula for density?
Density is the relationship between the mass and volume of a substance. It's how many atoms there are in a given amount of space.
D = M / V
Chemical changes are _____________.
irreversible
Molecules of a substance are farthest apart from each other in which state of matter?
Gases
Protons - positive
Electrons - negative
Neutrons - no charge
Most substances can exist as a solid, liquid, or gas depending on the _______________.
temperature
What is the difference between solubility, solute, solvent, and solution? Give an example of each.
Solubility is how much a substance can dissolve in another substance (ex. sugar has more solubility than oil in water)
A solute is the part of a solution that gets dissolved (ex. kool-aid powder), the solvent is the part of a solution that does the dissolving (water), and the solution is an equally proportioned mixture of the two substances (kool-aid)
On a hot summer day, you make a glass of refreshing sweet iced tea by combining boiling water, tea, sugar, and ice. What type of change occurs and how do you know?
Physical change - sugar dissolves in the tea and water, but the chemical composition remains unchanged. You can still recover the sugar by evaporating the water. (So remember, solubility is a physical property!)
Describe how a mercury thermometer records temperature changes (think about heat, atoms, expand, and contact).
When atoms are heated, they move more quickly, therefore expanding. This is how a mercury thermometer works. As the atoms in the thermometer heat up they expand and rise up the thermometer showing the temperature. When atoms are cooled, they move more slowly, therefore contracting. As the atoms in the thermometer cool down, they contract, and fall down the thermometer showing the temperature.