Exam 1

Question 1

Matter

Answer 1

anything that has mass and takes up space

Question 2

gas

Answer 2

no fixed volume or shape

Question 3

properties of gas

Answer 3

• molecules are far apart and under go frequent collisions
  
  • since they are moving so fast and random they can collide (there’s also a lot of them)
• if compressed in a fixed space more collisions happen

Question 4

liquid

Answer 4

fixed volume (independent of its container), no fixed shape

Question 5

properties of liquid

Answer 5

molecules are closely packed (linked with bonds) and move rapidly

Question 6

solid

Answer 6

fixed shape and fixed volume

Question 7

properties of solid

Answer 7

• molecules tightly held together
  
  • reason for the fixed shape

Question 8

Pure substances

Answer 8

have unique composition and does not vary from sample to sample; composition is constant (if the composition is not constant then it is not pure)

Question 9

Elements

Answer 9

Pure substances that cannot be broken down into simpler parts; make of only one type of atom (basic structure)

Question 10

molecule

Answer 10

the combination of two atoms

Question 11

Compounds

Answer 11

• pure substances made of two or more elements or atoms
  
  • Water (H2O), carbon dioxide (CO2)
• definite composition

Question 12

definite composition

Answer 12

• CO2 here and CO2 somewhere else has the same composition; relative number of atoms of each element in the compound is the same in any sample
  
  • Law of Constant Composition

Question 13

Homogeneous mixtures

Answer 13

• uniformly mixed on an atomic or molecular level
  
  • same things in one bite

Question 14

Heterogeneous mixtures

Answer 14

• not uniformly mixed on an atomic or molecular level
  
  • ex: distribution of toppings on pizza; the same things not guaranteed with each bite

Question 15

Methods to Separate Mixtures

Answer 15

Filtration, Distillation, Chromatography

Question 16

Filtration

Answer 16

• separating a solid component from the liquid component
• probably with filter paper

Question 17

Distillation

Answer 17

• separating liquids based on the boiling point of the liquid
• the liquid with the lowest boiling point will boil first
  
  • will vaporize and leave into the condenser
  • collect the vapor

Question 18

Chromatography

Answer 18

• mixture is put on top of the stationary phase (solid/sand-like)
• solvent is added on top (liquid)
  
  • will push the mixture through the stationary phase
• come out as drops

Question 19

different components will hold on to the stationary phase with a different strengths (chromatography)

Answer 19

• tight hold - come out last
• lose hold - come out first

Question 19

different components will hold on to the stationary phase with a different strengths (chromatography)

Answer 19

• tight hold - come out last
• lose hold - come out first

Question 20

Physical Properties

Answer 20

• can be observed without changing the identity or composition of the substance
  
  • ex: color, melting point, density, or conductivity

Question 21

Chemical Properties

Answer 21

• describes how a substance change or reacts to form other substances
  
  • reaction based