Average atomic mass
using Avogadro's #
Molar Mass conversions
Miscellaneous
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

1 mole = ? Liters

22.4

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

This is the % composition of C in CO2

What is 27.27%

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

These are the 4 steps needed to find the Empirical Formula

What is 1. Percent to grams  2. Convert to Moles  3. Divide by smallest Molar number  4. Multiply to get all whole numbers

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

MgOH2 has a Molecular Mass of 127. This is its Molecular Formula ____________.

What is Mg3O3H6

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

An unknown hydrocarbon is found to contain 96% carbon and has a molecular mass of 50 g/mol. What is its molecular formula?

H2C4

500
If asked to find the number of molecules, the given substances is a ______________.
What is a compound
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