Calculating Averages?
posted by Alison .
A certain element has four isotopes.
5.85% of has a mass of 53.93961 .
91.8% of has a mass of 55.934939 .
2.12% of has a mass of 56.93539 .
0.282% of has a mass of 57.93328 .
What is the average atomic mass of element ?
Express your answer numerically to three significant figures.

Calculating Averages? 
Alison
i got 56.2amu but it was wrong. i don't know how to find the average amu?

Calculating Averages? 
TutorCat
http://www.algebralab.org/practice/practice.aspx?file=algebra_averageatomicmass.xml

Calculating Averages? 
Reiny
I would suggest finding the 100% mass of each of the isotopes, adding those, then dividing by 4
I will find the 100% mass for the first one:
if 5.85% has a mass of 53.93961, then
100% has a mass of 53.93961/5.85*100 or 922.0446154
I could be way off base here, perhaps a chemist could enlighten us.
The webpage suggested by "TutorCat" makes sense to me. 
Calculating Averages? 
Kevin
just throwing out a number because i'm bored: 55.8741 was what i got. I'm no chemist, but i wanted to take a shot at it and now i'm curious how close the real answer is to mine.

Calculating Averages? 
A
55.8
Respond to this Question
Similar Questions

chemistry
The element copper has naturally occuring isotopes with mass numbers of 63 and 65. The relative abundance atomic masses are 69.2% for mass=62.93 amu, and 30.8% for mass=64.93 amu. Calculate the average atomic mass of copper. 
Chemistry
I need to find the average molar mass of an unknown element. The atomic mass is 120; the mass numbers of isotopes are 295, 296, 297, 298 and 299; the percent of each isotope is 2.356%, 4.325%, 15.652%, 48.452% and 29.215%. The mass … 
Chemistry
I need to find the average molar mass of an unknown element. The atomic mass is 120; the mass numbers of isotopes are 295, 296, 297, 298 and 299; the percent of each isotope is 2.356%, 4.325%, 15.652%, 48.452% and 29.215%. The mass … 
chemistry
Element x is composed of isotopes x56 mass 56.0 u and x59 mass 59.0 u. What is the percentage abundance of each of these isotopes if the atomic mass is 57.3 u? 
Chem
A newly discovered element, Mysternium (Atomic symbol My) has two isotopes and an average atomic mass of 296.7286 amu. One of the isotopes, My296 has a natural abundance of 61.528% and has a mass value of 295.9064 amu. What is the … 
chemistry
A hypothetical element has three main iso topes with mass numbers of 81, 83, and 84. If 17.00% of the isotopes have a mass number of 81 amu and 35.00% of the isotopes have a mass of 83 amu, what atomic weight should be listed on the … 
Science
A hypothetical element has two main isotopes with mass numbers of 56 and 59. If 61.00% of the isotopes have a mass number of 56 amu, what atomic weight should be listed on the periodic table for this element? 
Chemistry
1. A hypothetical pure element consists entirely of two isotopes. The natural percent abundance of the isotope with mass 25.5 u is 86.1%. The other isotope has mass 29.2 u. Calculate the atomic weight of the naturally occurring element. … 
Chemistry
An element has three stable isotopes. One has a mass number of 63 and an abundance of 50%. The second has a mass number of 65 and an abundance of 30%. The third has a mass number of 67 and an abundance of 20%. Calculate the relative … 
chemistry
A hypothetical element has two main isotopes with mass numbers of 71 and 74. If 80.00% of the isotopes have a mass number of 71 amu, what atomic weight should be listed on the periodic table for this element?