Scalar triple product

Find the volume of the parallelepiped with edges $\mathbf{a}=2\mathbf{i}$, $\mathbf{b}=3\mathbf{j}$, $\mathbf{c}=\mathbf{i}+\mathbf{j}+4\mathbf{k}$, meeting at a common vertex.

What does the scalar triple product $\mathbf{a}\cdot(\mathbf{b}\times\mathbf{c})$ represent geometrically when $\mathbf{a},\mathbf{b},\mathbf{c}$ are edges of a parallelepiped meeting at one vertex?

Show whether $\mathbf{a}=\mathbf{i}+\mathbf{j}$, $\mathbf{b}=\mathbf{j}+\mathbf{k}$, $\mathbf{c}=\mathbf{i}+2\mathbf{j}+\mathbf{k}$ are coplanar, by computing $\mathbf{a}\cdot(\mathbf{b}\times\mathbf{c})$.