Answer:
3.43 %
Explanation:
We need to calculate first the number of moles of CeO2 produced in the combustion. Given its formula we know how many moles of Ce atom are present. From there calculate the mass this number of moles this represent and then one can calculate the percentage.
0.1848 g CeO2 x 1 mol CeO2/172.114g = 0.00107 mol CeO2
0.00107 mol CeO2 x 1 mol Ce/ 1 mol CeO2 = 0.00107 mol Ce
.00107 mol Ce x 140.116 g Ce/ mol = 0.150 g Ce
0.150 g Ce/ 4.3718 g sample x 100 = 3.43 %
Answer:
Absorbed, endothermic
Explanation:
Based on the heat of reaction, chemical reactions may be classified as endothermic or exothermic.
In an endothermic reaction, heat is absorbed from the surrounding. As heat is absorbed from the surrounding, the reaction vessel feels cool when touched.
On the other hand, in an exothermic reaction, heat is given out by the system to the surrounding and the reaction vessel feels hot when touched.
Hence the reaction is endothermic and energy is absorbed during the reaction.
Not sure, is it <span>:
</span>B.
<span> 1.9 3 1027 NiCl2
formula units</span>
Answer: Explanation:
Calcium (Ca), chemical element, one of the alkaline-earth metals of Group 2 (IIa) of the periodic table. It is the most abundant metallic element in the human body and the fifth most abundant element in Earth's crust.
...
Calcium.
atomic number 20
oxidation state +2
electron configuration 1s22s22p63s23p64s2
Explanation:
