Answer:
(a) Heterogeneous mixture; (b) heterogeneous mixture;
(c) heterogeneous mixture; (d) homogeneous mixture; (e) pure substance.
Explanation:
(a) Concrete
Heterogeneous mixture. Concrete is a mixture of sand, gravel, and crushed stone held together with a cement.
In a heterogeneous mixture, you can see definite boundaries between the various components.
(b) Tomato juice
Heterogeneous mixture. It consists of water, tomato pulp, salt, and other substances.
(c) Marble
Heterogeneous mixture. It consists mostly of CaCO₃, but it usually contains other substances such as mica, quartz, pyrite, and iron oxides.
(d) Seawater
Homogeneous mixture. Seawater is an aqueous solution of NaCl along with other ions like Mg²⁺, Ca²⁺ ,and SO₄²⁻.
(e) Iron
Pure substance. Iron is an element. It consists only of Fe atoms.
