Multiple Choice
A small lead block has a mass of 6.8 g. How many atoms of lead (Pb) are present in the block? (Atomic mass of Pb = 207 g/mol, Avogadro's number = 6.022 × 10^{23} mol^{-1})
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2. Atoms & Elements
Mole Concept
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If you have 267 grams of aluminum chloride (AlCl_3), how many moles of AlCl_3 do you have?
A
1.50 moles
B
3.00 moles
C
0.50 moles
D
2.00 moles
Verified step by step guidance1
Identify the given information: mass of aluminum chloride (AlCl_3) is 267 grams.
Calculate the molar mass of AlCl_3 by adding the atomic masses of its elements: aluminum (Al) and chlorine (Cl). Use the atomic masses: Al = 26.98 g/mol, Cl = 35.45 g/mol. The formula is \(\text{Molar mass of AlCl}_3 = 26.98 + 3 \times 35.45\) g/mol.
Use the formula to find moles: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\).
Substitute the values into the formula: \(\text{moles of AlCl}_3 = \frac{267 \text{ g}}{\text{molar mass of AlCl}_3}\).
Perform the division to find the number of moles of AlCl_3.
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