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
calculate the molar mass of NaCl
What is 58.44 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 (NH4)2SO4?
What is 132.14 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 8.23 moles of CaCl2?
What is 8.23 mol x (110.98g / 1 mol) = 913 g CaCl2
400
How many molecules are in 52g of KPO4?
What is 52g x (1 mol / 134.068 g) x (6.02 E 23 atoms / 1 mol) = 2.3 x 10^23 molecules KPO4
400
= 6.02 x 10^23 atoms or molecules
What is a mole
500
Given the average atomic mass of Boron, what are the relative abundances of the isotopes B-10 and B-11?
What is B-10 ~20% B-11 ~80%
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 2.8 moles of (NH4)2CO3?
What is 2.8 mol x (96.09g / 1 mol) = 269.052 = 2.7 x 10^2 g (NH4)2 CO3
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
If asked to find the number of molecules, the given substances is a ______________.
What is a compound
M
e
n
u