Avogadro's Constant and the Mole

Question 1

g –> kg

Answer 1

/1000

Question 2

kg —> g

Answer 2

x 1000

Question 3

what would we always do when calucting equations

Answer 3

• Use SD for +/- and x/ dividing
• EVERY line need a unit in an equation
• ## Write therofore ststament

Question 4

Relating mass on the scale (grams) to the number of molecules

Answer 4

• You cannot physically count the molecules in a substance (very small)
• You can not weight each molecule because 1 molecules of a substance does not equal 1 molecule of another
• We use moles as they are different for every substance
• Moles are converted into mass (using molar mass) as we can only measure by weight

Question 5

Mole

Answer 5

• A unit for counting entities
• Entities: ionic compound= formula unit, pure element= molecules, atoms
• 1 mole= 6.022x10^23 entities
• 1 mole of every substance is different because they do not weigh the same

Question 6

Avogadro’s constant

Answer 6

• 1 mole of C-12 atoms is equal to the mass of C-12 (12 g)
• Same for other elements as well
• Named after Amedeo Avogadro
• 6.022x10^23 was chosen because it’s the number of atoms in exactly 12 g of carbon

Question 7

Mol

Answer 7

• The unit of mole
• Can be made up of units of atoms OR units of molecules OR units of formula units
• Etnies name changes to formula units, atoms, molecules, etc

Question 8

Molar Mass (M)

Answer 8

• G / mol
• The mass of an element on periodic table
• Mass per mole

Question 9

Molar Mass of Compounds

Answer 9

• Sum of the molar mass of each entity in a compound

Question 10

Relationship between mass, moles, and molar mass

Answer 10

• To find mass, you find the molar mass and multiple the # of moles
• Equations are arranged depending on question
  m=nM

Question 11

mg –> g

Answer 11

/1000

Question 12

g —> mg

Answer 12

x 1000

Question 13

m

Answer 13

mass in grams

Question 14

n

Answer 14

number of moles

Question 15

M

Answer 15

molar mass (in g/mol)