Answer:
3.98 g
Explanation:
Step 1. Write the balanced chemical reaction. In this case, magnesium reacts with oxygen to produce magnesium oxide:
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Step 2. Calculate the number of moles of magnesium:
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Step 3. Calculate the number of moles of oxygen:
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Step 4. Identify the limiting reactant comparing the equivalents. Equivalent of Mg:
Equivalent of oxygen:
Therefore, Mg is the limiting reactant.
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Step 5. According to the stoichiometry of this reaction:
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Step 6. Convert the number of moles of MgO into mass:
The identity of a metal that has a mass of 27.0g and a volume of 10.0cm is Aluminium. That is option B.
<h3>What is molar mass?</h3>
Molar mass is defined as the mass in grams of one mole of an element. This is measured in grams/mole of that substance.
The metal that is 27.0 g and a volume of 10.0 cm3 is aluminium because aluminium is 27 times heavier than 1/12th of the mass of carbon-12 atom.
Therefore, the identity of a metal that has a mass of 27.0g and a volume of 10.0cm is Aluminium.
Learn more about molar mass here:
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Answer:
Mole fraction H₂O → 0.72
Mole fraction C₂H₅OH → 0.28
Explanation:
By the mass of the two elements in the solution, we determine the moles of each:
25 g . 1 mol/ 18g = 1.39 moles of water (solute)
25 g . 1 mol / 46 g = 0.543 moles of ethanol (solvent)
Mole fraction solute = Moles of solute / Total moles
Mole fraction solvent = Moles of solvent / Total moles
Total moles = Moles of solute + Moles of solvent
1.39 moles of solute + 0.543 moles of solvent = 1.933 moles → Total moles
Mole fraction H₂O = 1.39 / 1.933 → 0.72
Mole fraction C₂H₅OH= 0.543 / 1.933 → 0.28
Remember that sum of mole fractions = 1
Answer:
to be honest ask your teacher
