Chapter 1 (What is Chemistry?)

Question 1

macroscopic scale

Answer 1

what can be seen with the naked eye

Question 2

atomic scale

Answer 2

(aka nanoscale or microscale)

what chemists use to describe atoms or molecules

Question 3

When do chemists use macroscopic/microscopic scale?

Answer 3

macro-observations

micro-describing chemical processes at atomic level

Question 4

matter description

Answer 4

collection of characteristics called properties

Question 5

element

Answer 5

simplest type of matter that can’t be broken down into simpler substances

Question 6

atom

Answer 6

smallest indivisible unit of an element.

Question 7

Method that scientists use to view atoms

Answer 7

Scanning Tunneling Microscopy (STM)

Question 8

chemical compound

Answer 8

substance formed when two or more elements are combined in a defined ratio

Question 9

How are compounds different from elements?

Answer 9

compounds can be broken down chemically into simpler substances

Question 10

molecules

Answer 10

collections of atoms held together by chemical bonds

Question 11

pure substance

Answer 11

• contains only one type of element or compound
• has a fixed chemical substance
• has characteristic properties(measurable qualities that are independent of sample size)

Question 12

physical properties

Answer 12

do not change the chemical composition of the matter when they are measured

Question 13

chemical properties

Answer 13

• changes chemical composition of the matter when measured
• often involves interaction with other chemicals (ex: methanol CH3OH is highly flammable bc it reacts w/ oxygen in the air and forms water and carbon dioxide)

Question 14

solid

Answer 14

• dense material
• defined shape
• atoms or molecules packed together closely
• atoms or molecules vibrating but not moving past each other

Question 15

liquid

Answer 15

• dense
• flows and takes shape of container
• atoms or molecules can move past one another

Question 16

gas

Answer 16

• no fixed shape or volume
• atoms or molecules spaced far apart and moving past each other rapidly
• particles do not strongly interact w/ each other

Question 17

melting point

Answer 17

the temperature at which a solid is converted to liquid when energy is added
(same temp as freezing point)

Question 18

freezing point

Answer 18

temperature at which a liquid is converted to a solid when energy is removed
(same as melting point)

Question 19

boiling point

Answer 19

where liquid is converted to gas

Question 20

mixture

Answer 20

• substance made up of 2 or more elements or compounds that haven’t reacted chemically
• can usually by physically separated into individual components

Question 21

homogenous mixture

Answer 21

mixtures w/ constant composition throughout (ex:salt water)

Question 22

heterogeneous mixture

Answer 22

mixtures w/ inconsistent composition (ex:lemonade)