Does work equal heat?

The explanation of conversion of heat into work is explained in below points:

1. From the $2\mathrm{nd}$ law of thermodynamics, the random molecules of heat can't be fully converted into organized molecules of work.
2. Efficiency of heat engine is defined as the work done in a cyclic process divided by heat absorbed.
3. The principle application can be seen in heat engine, where efficiency of the engine is always less than $1$.
   Therefore, the conversion of heat into work is explained in above points.