Answer:
This question is incomplete
Explanation:
This question is incomplete as the volume of the base that was used during the titration was not provided. However, the completed question is in the attachment below.
The formula to be used here is CₐVₐ/CbVb = nₐ/nb
where Cₐ is the concentration of the acid = unknown
Vₐ is the volume of the acid used = 25 cm³ (as seen in the question)
Cb is the concentration of the base = 0.105 mol/dm³ (as seen in the question)
Vb is the volume of the base = 22.13 cm³ (22.1 + 22.15 + 22.15/3)
nₐ is the number of moles of acid = 1 (from the chemical equation)
nb is the number of moles of base = 2 (from the chemical equation)
Note that the Vb was based on the concordant results (values within the range of 0.1 cm³ of each other on the table) of the student
Cₐ x 25/0.105 x 22.13 = 1/2
Cₐ x 25 x 2 = 0.105 x 22.13 x 1
Cₐ x 50 = 0.105 x 22.13
Cₐ = 0.105 x 22.13/50
Cₐ = 0.047 mol/dm³
The concentration of the sulfuric acid is 0.047 mol/dm³
Answer:
Aluminium atoms = 4.13 *10^22 aluminium atoms
The correct answer is E
Explanation:
Step 1: Data given
Mass of Al2O3 = 3.50 grams
Molar mass of Al2O3 = 101.96 g/mol
Number of Avogadro = 6.022 * 10^23 /mol
Step 2: Calculate moles Al2O3
Moles Al2O3 = mass Al2O3 / molar mass Al2O3
Moles Al2O3 = 3.50 grams / 101.96 g/mol
Moles Al2O3 = 0.0343 moles
Step 3: Calculate moles Aluminium
In 1 mol Al2O3 we have 2 moles Al
in 0.0343 moles Al2O3 we have 2*0.0343 = 0.0686 moles Al
Step 4: Calculate aluminium atoms
Aluminium atoms = moles aluminium * Number of Avogadro
Aluminium atoms = 0.0686 * 6.022 * 10^23
Aluminium atoms = 4.13 *10^22 aluminium atoms
The correct answer is E
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