Question

you have 10.0 g each of na, c, pb, cu and ne. which contains the largest number of moles? a cu b na c pb d c

Explanation:

Step1: Recall the formula for moles

The formula for calculating the number of moles \(n=\frac{m}{M}\), where \(m\) is the mass and \(M\) is the molar mass. Given \(m = 10.0\space g\) for all substances, the substance with the smallest molar mass \(M\) will have the largest number of moles \(n\).

Step2: Find the molar masses

• Molar mass of \(Cu\): \(M_{Cu}=63.55\space g/mol\)
• Molar mass of \(Na\): \(M_{Na}=22.99\space g/mol\)
• Molar mass of \(Pb\): \(M_{Pb}=207.2\space g/mol\)
• Molar mass of \(C\): \(M_{C}=12.01\space g/mol\)

Step3: Compare the molar masses

Since \(12.01\space g/mol(M_{C})<22.99\space g/mol(M_{Na})<63.55\space g/mol(M_{Cu})<207.2\space g/mol(M_{Pb})\)

Answer:

D. C