Question

the mass of 0.250 moles of c₆h₆ is ______. 19.5 grams 14.2 grams 1.53 grams 9.53 grams question 18 one mole of glycine, c₂h₅o₂n, contains 2 moles of carbon, 5 moles of hydrogen, 2 moles of oxygen, and 1 mole of nitrogen and weighs ______. 75.08 grams 88.02 grams 7.36 grams 68.1 grams

Explanation:

Step1: Calculate molar - mass of \(C_6H_6\)

The molar - mass of carbon (\(C\)) is approximately \(12.01\ g/mol\) and hydrogen (\(H\)) is approximately \(1.01\ g/mol\). For \(C_6H_6\), \(M = 6\times12.01+6\times1.01=72.06 + 6.06=78.12\ g/mol\).

Step2: Calculate mass of \(0.250\) moles of \(C_6H_6\)

Using the formula \(m=n\times M\), where \(n = 0.250\ mol\) and \(M = 78.12\ g/mol\), then \(m=0.250\times78.12 = 19.53\approx19.5\ g\).

Step3: Calculate molar - mass of glycine \(C_2H_5O_2N\)

The molar - mass of \(C\) is \(12.01\ g/mol\), \(H\) is \(1.01\ g/mol\), \(O\) is \(16.00\ g/mol\), and \(N\) is \(14.01\ g/mol\).
\(M = 2\times12.01+5\times1.01+2\times16.00 + 1\times14.01\)
\(=24.02+5.05 + 32.00+14.01\)
\(=75.08\ g/mol\)

Answer:

The mass of \(0.250\) moles of \(C_6H_6\) is: A. 19.5 grams
One mole of glycine, \(C_2H_5O_2N\), weighs: A. 75.08 grams