Question

exit ticket: moles
4 fill in the blank 1 point
calculate the mass of 6.23 moles of li₂s
answer = grams (round answer to 2 decimal points)

Explanation:

Step1: Calculate molar mass of \(Li_2S\)

Atomic mass of \(Li = 6.94\space g/mol\), atomic mass of \(S=32.07\space g/mol\).
Molar mass of \(Li_2S=(2\times6.94 + 32.07)\space g/mol=(13.88+32.07)\space g/mol = 45.95\space g/mol\)

Step2: Use the formula \(m = n\times M\)

where \(n = 6.23\space mol\) (number of moles) and \(M = 45.95\space g/mol\) (molar mass).
\(m=6.23\times45.95\space g\)
\(m = 6.23\times45.95=6.23\times(46 - 0.05)=6.23\times46-6.23\times0.05\)
\(=286.58- 0.3115=286.2685\approx286.27\space g\)

Answer:

\(286.27\)