Answer:
2023.04 g
Explanation:
Magnetite reacts with hydrogen to produce Iron metal and steam. Steam instead of water is produced as the reaction occurs at temperatures above the boiling point of water.
Fe₃O₄ + 4 H₂ → 3 Fe +4 H₂O
From the equation, 1 mole of Fe₃O₄ reacts with 4 moles of H₂.
69.76 grams of H₂ has the following number of moles.
Number of moles= mass/RAM
=69.76/2
=34.88 moles.
The reaction ratio of Fe₃O₄ to H₂ is 1:4
Thus number of moles of magnetite= (1×34.88)/4
=8.72 moles.
Mass= moles × molecular weight
=8.72 moles × (56×3+16×4)
=2023.04 grams
Answer:
1.30464 grams of glucose was present in 100.0 mL of final solution.
Explanation:

Moles of glucose = 
Volume of the solution = 100 mL = 0.1 L (1 mL = 0.001 L)
Molarity of the solution = 
A 30.0 mL sample of above glucose solution was diluted to 0.500 L:
Molarity of the solution before dilution = 
Volume of the solution taken = 
Molarity of the solution after dilution = 
Volume of the solution after dilution= 



Mass glucose are in 100.0 mL of the 0.07248 mol/L glucose solution:
Volume of solution = 100.0 mL = 0.1 L

Moles of glucose = 
Mass of 0.007248 moles of glucose :
0.007248 mol × 180 g/mol = 1.30464 grams
1.30464 grams of glucose was present in 100.0 mL of final solution.
Answer:
carbon dioxide CO₂
Explanation:
Each gas has a characteristic boiling point. You can separate a random sample of gases by gradually cooling the sample until each component gas liquifies. Some compounds, such as CO₂ never liquify. Instead, they turn directly into solids.
Arsenic, I believe. Metalloids fall in between metals and nonmetals (usually on the bold line separating the two on the periodic table). And since the metalloid in question has four electron shells and five valence electrons in the outermost shell, you can see that this element is arsenic