HELP! Calculate the magnesium number for each lava. The Mg# is the atomic ratio
ID: 231087 • Letter: H
Question
HELP!
Calculate the magnesium number for each lava. The Mg# is the atomic ratio of 100 x Mg/(Mg + Fe2+). To get the atomic ratio, you will have to divide the oxide weights of MgO and FeO by their molecular weights.
This is the chart:
So I have the molecular weights for the elemets:
Fe 2=55.845
Mg= 240305
O= 15.9994
FeO= 710844 g/mol
MgO= 40.3044 g/mol
Mg+Fe= 80.1895
So then what do I do from there? plug it in 100 x Mg/(Mg + Fe2+)
100 x 24.305/80.1895= 30.309 and thats it...how does the chart come into play?
KilaueaLavasRawData xls Download KlaueaLavasRawData xis (27 5 KB) Analyses of lavas from Kilauea, Hawail Source: Philpotts, Principles of Igneous and Metamorphic Petrology. 1990, Table 13-1 lavas 1 2 3 4 5 6 7 8910 1 121 14 1s 16 sio2 48.05 48.43 47.92 48.21 49.16 49.20 49.71 50.10 50.37 50.56 50.74 50.85 50.92 51.24 5342 40.01 Al203 10.33 10.70 10.75 11.37 13.33 12.77 1365 1378 14.02 1392 1357 14.02 13.80 13.60 13.75 113 olivine wt% TiO2 2.04 2.00 2.16 2.24 2.29 2.57 268 2.71 3.09 3.16 3.35 3.36 361 374 3.36 0.04 Fe203 1.34 1.15 1.08 150 131 1.50 119 189 1.88 1.78 136 190 185 187 196 0.30 10.19 10.08 10.65 10.18 9.71 1005 9.72 9.46 10.07 10 18 10.63 10.44 10.71 1119 10.45 12.33 0.17 0.17 0.18 018 016 0.17 017 017 017 018 0.18 018 019 018 01 017 Feo Mgo 17.39 16.29 15.43 13.94 10.41 1000 824 7.34 675 6.33 6.16 5.68 546 512 3924477 cao Na20 K20 P205 8.14 8,67 9.33 9.74 1093 10.75 11.59 1146 10.39 10.24 994 9.71 945 903 7.75 123 1.66 1.71 1.79 189 2 0.36 0.35 0.44 044 051 0.51 0.54 057 0.62 064 067 074 0.75 0.83 0.19 0.18 023 0.22 016 0.25 0.25 0.27 032 0.33 037 030 0.40 0.41 059 0. 2.15 2.12 226 2.25 2.35 261 269 277 2.80 281 334 001 0.67 0.74 0.75 0.83 1.10 0.00 66 ### 99.94 ### 9982 99.99 PrevicExplanation / Answer
the chart provides you the values of MgO and FeO.
the values will be different for each lava sample because the compositions are different.
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