classify each of the following as a pure substance or a mixture; if it is a mixture, state whether it is heterogeneous
o bomogeneous: (a) concrete, (btomato juice. (c) marble, (d) seawater, and (e) iron.

(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.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa