Classifying Matter
A Bowl of Cereal and Milk
Element? Compound? Heterogeneous Mixture? Homogenous Mixture?
Heterogeneous mixture! We have more than one compound/substance in the bowl and the cereal and milk is not evenly mixed.
Boiling Water
Physical or chemical change?
Physical change! The water is only changing states from liquid to gas.
True! Luster describes how shiny and object is which is a physical property!
Which of the following is not a physical property?
color, density, flammability, freezing point
Flammability! Remember, that is a chemical property!
What is Brownian motion?
Copper (II) Sulfate (CuSO4)
Element? Compound? Heterogeneous Mixture? Homogenous Mixture?
Compound! It has more than one type atom!
Burning Gasoline in an Engine
Physical or chemical change?
Chemical! That gas is burning and changing its chemical composition.
(True/False) The attractive forces between the atoms in solid iron are greater than the attractive forces between molecules of liquid water.
The law of conservation of matter states...
Matter cannot be created nor destroyed, it can only changes forms, and the amount of matter cannot change.
Also, bonus thinking! Remember from chapter 1 that a law only describes a phenomenon. It does not explain why.
How is it possible that at 101 degrees Celsius, water is a gas, mercury is a liquid, and titanium is a solid?
Each of these substances has different attractive forces between them. Water is a gas because at that temperature, it has enough kinetic energy to overcome the attractive forces between its particles. Mercury has a medium attractive force. And at that temperature, titanium has a high attractive force.
A Cup of Coffee (Hint: Coffee is made with coffee beans and hot water)
Element? Compound? Heterogeneous Mixture? Homogenous Mixture?
Homogenous Mixture! More than one substance and the coffee is evenly distributed through the hot water!
Grinding Coffee Beans
Physical or chemical change?
Physical! We are just changing the shape and size of the coffee beans to make them smaller.
(True/False) A solid must either melt and then evaporate or boil in order to become a gas.
False! Sublimation is when a solid goes straight to a gas (Think dry ice: solid, frozen carbon dioxide sublimates to create fog in fog machines)
Atoms consist of all of the following except:
electrons, molecules, neutrons, protons
Molecules! Atoms are made of protons, neutrons, and electrons and make up molecules!
Explain how matter is classified.
Matter is first classified as either a pure substance or a mixture. If the material is only made of one type of atom it is an element. If it is made of two or more types of atoms, it is a compound. If the mixture has substances that are unevenly mixed, it is heterogeneous. If the mixture has substances that are evenly mixed, it is homogenous.
Oxygen
Element? Compound? Heterogeneous Mixture? Homogenous Mixture?
Element! There is only one type of atom, oxygen! When in doubt, come look at the periodic table at the front of the classroom or ask me if it is on the periodic table.
Ice Crystals on a Frosty Morning
Physical or chemical change?
Physical! The ice is changing states from a gas to a solid (deposition) on cold windows.
(True/False) The SI Unit for both mass and weight in the gram.
False! Mass is in grams, but what is weight measured in? (Hint: Who invented the laws of gravity?)
What state of matter does not experience particle motion? Solid, Liquid, Gas, or Plasma? (Hint: it's a trick question!)
None of the above! All states of matter experience some particle motion!
Are the particles found in solid iron moving? Explain. What would happen to the particles if the iron bar is heating to its melting point?
Yes, the particles are moving very little, but still moving. Solid particles vibrate in place. As the iron bar was heated to its melting point, the particles would gain energy. Once the iron bar reaches its melting point, the particles will have enough energy to slightly overcome the attractive forces between them and become liquid iron.
Table Salt (NaCl)
Element? Compound? Heterogeneous Mixture? Homogenous Mixture?
Compound! There is only one kind of substance in the container, but there are two types of atoms!
Mixing Chemical A with Chemical B to Form Chemical C
Physical or Chemical Change?
Chemical! A chemical reaction has taken place to form a brand new chemical that wasn't there before!
(True/False) The melting point for a pure substance is the same as its freezing point.
True! Ice will melt to a liquid at 32 degrees and liquid water will turn to ice at 32 degrees.
A diamond is compromised of a repeated pattern of carbon atoms. Is it an amorphous solid or a crystalline sold?
Crystalline solid! Diamonds form distinct, geometric shapes.
Explain the difference between mass and weight.
Mass is the amount of matter in an object and is measured in grams. Weight is the measure of gravity acting on the matter and is measured in Newtons. Weight can change depending on your location (Ex: Earth vs. Moon), but mass does not change.