Answer/explanation :
To calculate the number of mass, we use this formula
Number of mole = mass / molar mass
Since we are given the number of mole
Number of mole = 2.60mol
Mass = ?g
Molar mass of Li = 6.941g/mol
2.60mol = mass / 6.941 g/mol
Mass = 2.60 * 6.941
= 18.0466g
Therefore, the number of mass is 18.0466g
