Question

▲1-70 assign each of the following descriptions of matter to one of the following categories: element, compound, or mixture
a. two substances present, one phase present, all molecules present are heteroatomic
b. one substance present, two phases present, one kind of heteroatomic molecule present
c. one phase present; all molecules are triatomic, heteroatomic, and identical
d. diatomic, homoatomic, and triatomic heteroatomic molecules are present

Explanation:

Part a

Step1: Recall definitions

• Element: Pure substance with homoatomic molecules (same atoms).
• Compound: Pure substance with heteroatomic molecules (different atoms), single substance.
• Mixture: Two or more substances, can be same or different phases.

Here, two substances (so mixture candidate), one phase, heteroatomic molecules (but two substances mean mixture, as compounds have one substance).

Step2: Classify

Two substances → mixture (even with one phase, multiple substances).

Part b

Step1: Recall definitions

One substance (so pure), two phases (e.g., ice and water), heteroatomic molecule (compound has heteroatomic, element has homoatomic).

Step2: Classify

One substance (pure), heteroatomic → compound (can have phases, like $H_2O$ solid and liquid).

Part c

Step1: Recall definitions

One phase, all molecules identical (one substance), triatomic heteroatomic (different atoms, three per molecule).

Step2: Classify

One substance, heteroatomic → compound (pure, single substance with different atoms).

Part d

Answer:

s:
a. mixture
b. compound
c. compound
d. mixture