Answer:
A
Explanation:
Lanthanides share the following common properties: Silvery-white metals that tarnish when exposed to air, forming their oxides. Relatively soft metals. Hardness increases somewhat with higher atomic number.
Answer;
-(2) An atom is mostly empty space.
Experiment
-Rutherford conducted the "gold foil" experiment where he shot alpha particles at a thin sheet of gold. The conclusion that can be drawn from these experiment is that an atom is mostly empty space.
-Rutherford found that a small percentage of the particles were deflected, while a majority passed through the sheet. This caused Rutherford to conclude that the mass of an atom was concentrated at its center, as the tiny, dense nucleus was causing the deflections.
We have to solve this question using the stoichiometry of the reaction:
The equation of the reaction is;
According to the question;
Number of moles of CO2 released = 21.3 g/44 g/mol = 0.48 moles
From the stoichiometry of the reaction:
Since;
24 moles of CO2 released 15,026 KJ
0.48 moles of CO2 will release 0.48 * 15,026/24
= 301 KJ of heat.
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Answer:
d. 12.3 grams of Al2O3
Explanation:
Based on the reaction:
4Al + 3O2 → 2Al2O3
<em>Where 4 moles of Al reacts in excess of oxygen to produce 2 moles of aluminium oxide.</em>
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To solve this question we must find the moles of Aluminium. With these moles we can find the moles of aluminium oxide using the reaction:
<em>Moles Al -Molar mass: 26.9815g/mol-</em>
6.50g * (1mol / 26.9815g) = 0.241 moles Al
<em>Mass Al₂O₃ -Molar mass: 101.96g/mol-</em>
0.241 moles Al * (2 mol Al2O3 / 4 mol Al) = 0.120 moles Al2O3
0.120 moles Al2O3 * (101.96g / mol) =
12.3g of Al2O3 are produced.
Right answer is:
<h3>d. 12.3 grams of Al2O3
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