Question

bnoer chemistry
name:
chemistry matter review practice

1. match each diagram with its correct description. diagrams will be used once. note: each circle represents an atom. if two atoms are touching, then they are bonded together and are a compound.

diagrams labeled a, b, c, d, e
__1. pure element = only one type of atom present.
__2. mixture of two elements = two types of uncombined atoms present.
__3. pure compound = only one type of compound present.
__4. mixture of two compounds = two types of compounds present.
__5. mixture of a compound and an element.

1. read each description and determine whether it is a pure substance or mixture. then further classify the matter (element, compound, homogeneous mixture, heterogeneous mixture).

description | pure substance or mixture? | classification?

1. chocolate syrup is added to milk and stirred | mixture | homogenous mixture (solution)
2. copper metal (used to make wires) | |
3. sand is added to water | |
4. distilled water | |
5. tap water | |
6. helium gas (used to inflate a balloon) | |
7. table sugar | |
8. table sugar added to a cup of coffee and stirred | |
9. the air we breathe | |

Answer:

Part 1: Matching Diagrams

1. Pure Element (only one type of atom)

• Diagram C has only one type of atom (all circles are the same). So 1 - C.

2. Mixture of two elements (two uncombined atoms)

• Diagram E has two types of uncombined atoms (different colored circles, not bonded). So 2 - E.

3. Pure compound (only one compound)

• Diagram D has molecules of one compound (same bonded groups). Wait, no—wait, pure compound is one type of compound. Wait, let's recheck: Diagram D: Wait, no, let's see: Pure compound is when all molecules are the same compound. Wait, maybe I messed up. Wait, pure compound: atoms bonded in the same way, one type. So Diagram D? No, wait, let's look again. Wait, pure compound: only one type of compound. So if a diagram has only one kind of molecule (bonded atoms), that's pure compound. Let's check the diagrams:

• Diagram D: Let's see the circles. Wait, maybe I made a mistake. Wait, pure compound: all molecules are the same. So let's re-express:

• Pure Element: C (all same atoms, not bonded, single type).

• Mixture of two elements: E (two types of atoms, not bonded, mixed).

• Pure compound: D? Wait, no, maybe D is a mixture? Wait, no. Wait, the problem says: "each circle represents an atom. If two atoms are touching, then they are bonded together and are a compound."

So:

• Diagram A: two types of compounds (two different bonded groups) → mixture of two compounds.

• Diagram B: one compound and one element (some bonded, some single) → mixture of compound and element.

• Diagram C: single type of atom, not bonded → pure element.

• Diagram D: single type of compound (all bonded groups same) → pure compound.

• Diagram E: two types of atoms, not bonded → mixture of two elements.

So:

1. Pure Element: C → 1 - C

1. Mixture of two elements: E → 2 - E

1. Pure compound: D → 3 - D

1. Mixture of two compounds: A (two different bonded compounds) → 4 - A

1. Mixture of compound and element: B (one compound, one element) → 5 - B

Part 2: Classifying Matter

We analyze each description:

Description	Pure Substance or Mixture?	Classification?
2. Copper metal	Pure Substance	Element (Cu is an element)
3. Sand + water	Mixture	Heterogeneous (sand doesn’t dissolve, visible particles)
4. Distilled water	Pure Substance	Compound (H₂O, made of two elements)
5. Tap water	Mixture	Homogeneous (contains dissolved minerals, uniform)
6. Helium gas	Pure Substance	Element (He is an element)
7. Table sugar	Pure Substance	Compound (C₁₂H₂₂O₁₁, made of C, H, O)
8. Sugar + coffee, stirred	Mixture	Homogeneous (solution, uniform)
9. The air we breathe	Mixture	Homogeneous (mixture of gases, uniform)

Final Answers (Part 1 Matching)

1. C
2. E
3. D
4. A
5. B

Final Table (Part 2 Classification)

Description	Pure Substance or Mixture?	Classification?
2. Copper metal (used to make wires)	Pure Substance	Element
3. Sand is added to water	Mixture	Heterogeneous mixture
4. Distilled water	Pure Substance	Compound
5. Tap water	Mixture	Homogeneous mixture
6. Helium gas (used to inflate a balloon)	Pure Substance	Element
7. Table sugar	Pure Substance	Compound
8. Table sugar added to a cup of coffee and stirred	Mixture	Homogeneous mixture (solution)
9. The air we breathe	Mixture	Homogeneous mixture