D. Has a uniform composition and is only able to be separated by chemical means.
Answer:
Option A) oxygen
Explanation:
Oxygen gas it the electrolysis of an aqueous solution of sodium nitrate which a gas forms at anode it is called the oxygen gas
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FeCO3 ==> Fe + produsi minoritari.
m Fe impur= 700 kg
puritatea (p) = masa pura (mp)/ masa impura (mi) x 100
mp= p x mi / 100 sau mp = p/100 x mi => mp Fe = 90/100 x 700 = 630 kg Fe pur.
M FeCO3= 115.85 kg/kmol
115.85 kg FeCO3 .... 55.85 kg Fe
x kg FeCO3 ........630 kg Fe
x= 630 * 115.85 /55.85 = 1306.81 kg FeCO3 (mp in formula puritatii)
p=mp/mi x 100
mi FeCO3 = 1500 kg
mp FeCO3=1306.81 kg
p=1306.81 / 1500 x 100 = 87.12% puritate Siderit
I don't know exactly what you are learning, but i know that chemistry involves the practice of mixing chemicals together to see what kind of reaction they make, if they make a reaction at all.