Average atomic mass
using Avogadro's #
Molar Mass conversions
Multi-Step Problems
Vocabulary
100
To calculate average atomic mass you must know the masses and ___________________ of the isotopes for that element.
What is relative abundance / % abundance
100
what is avogadro's #?
What is 6.02 x 10^23
100

the molar mass of Nb

What is 92.9064 g/mol

100
set up the following problem so that all of the unwanted units cancel out...do fill in numbers and do not solve!!! How many atoms are in 24g of Calcium?
What is 24g Ca x (____mol / ____ g) x (____ atoms / ______ mol)
100
the units for this term are g/mol
What is molar mass
200
Given the following information about an element, fill in the blanks to calculate average atomic mass. C-12 = 99% C-13 = 1% ( ____ x ____ ) + (_______ x ______) = avg. atomic mass DO NOT SOLVE THE PROBLEM
What is ( 12 x .99) + (13 x .01) = avg atomic mass
200

how many molecules are in one mole of NaCl

What is 6.02 x 10^23 molecules NaCl

200

What is the molar mass of arsenic?

What is 74.9216 g/mol

200
What number always goes with "moles" in the conversion factors we have used in this unit?
What is 1 mole
200
this number found on the periodic table is a weighted average of all isotopes of that element
What is average atomic mass
300
calculate average atomic mass given the following information: O-15 = 2% O-16 = 98%
What is (15 x 0.02) + (16 x .98) = 15.98 amu
300
How many moles are in 3.2 x 10^24 atoms of Cl?
What is 3.2E24 / 6.02E23 = 5.3 moles Cl
300
How many moles are in 3.25g of Sodium?
What is 3.25 g x (1 mol / 22.99g) = 0.141 mol Na
300
avogadro's number always goes with the units ___________ or ______________ as a conversion factor.
What is atoms, molecules
300
hydrogen is an example of a(n) ________
What is element
400
Based on the average atomic mass of Potassium, which isotope is more prevalent K-39 or K-40?
What is K-39
400
How many molecules are in 6.5 moles of water?
What is 6.5 x 6.02 E23 = 3.9 x 10^24 molecules H2O
400

How many grams are in 8.21 moles of calcium?

What is 8.21 mol x (40.078 g / 1 mol) = 329 g Ca

400

How many molecules are in 52g of phosphorous?

What is 52g x (1 mol / 30.9737 g) x (6.02 E 23 atoms / 1 mol) = 1.0 x 10^24 molecules P

400
= 6.02 x 10^23 atoms or molecules
What is a mole
500

Identify the element by it's average atomic mass that has these isotopes: X-11, 80% and X-10, 20%

What is Boron?

500
Is there more or less than one mole in 6.87 x 10^22 atoms of Hydrogen? calculator use not allowed!!!
What is less than 6.87 x 10^22 < 6.02 x 10^23
500

How many grams are in 2.824 moles of silver?

What is 2.824 mol x (107.868 g / 1 mol) = 304.6 g silver

500
How many grams are in 5.3 x 10^23 molecules of water?
What is 5.3 E23 molecules x (1 mol / 6.02 E 23 molecules) x (18.015 g / 1 mol) = 15.86 = 16 g H2O
500

6.022 x 1023 atoms or molecules?

Avogadro's number

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