Question

practice: classification
part 1: classify the following as a substance (s) or a mixture (m)

1. table salt (nacl)
2. trail mix
3. sugar
4. copper
5. cereal
6. concrete

part 2: classify the following substances as elements (e) or compounds (c)

1. mercury
2. water
3. carbon dioxide
4. iron
5. aluminum
6. oxygen (o₂)

part 3: classify the following mixtures as homogeneous (ho) or heterogeneous (he)

1. coffee
2. pizza
3. sand
4. saltwater
5. bronze
6. milk
7. paint
8. air
9. soil

part 4: classify the following as an element (e), compound (c), homogeneous mixture (ho) or heterogeneous mixture (he)

1. calcium
2. hydrogen (h₂)
3. orange juice with pulp
4. baking soda (nahco₃)
5. helium
6. limestone (caco₃)
7. salad dressing
8. vinegar (ch₃cooh)

part 5: each of the following circles represents an atom. if two atoms are touching then they are bonded together. knowing this, classify each picture as one of the following:
a - element
b - compound
c - mixture of elements
d - mixture of compounds
e - mixture of elements and compounds

Explanation:

Step1: Recall definitions

Elements are pure substances made of only one - type of atom. Compounds are pure substances made of two or more different types of atoms chemically bonded. Homogeneous mixtures have a uniform composition throughout, and heterogeneous mixtures have a non - uniform composition.

Step2: Analyze Part 1

Table salt (NaCl) is a compound (substance), trail mix is a mixture, sugar is a compound (substance), copper is an element (substance), cereal is a mixture, concrete is a mixture.

Step3: Analyze Part 2

Mercury is an element, water is a compound, carbon dioxide is a compound, iron is an element, aluminum is an element, oxygen ($O_2$) is an element.

Step4: Analyze Part 3

Coffee is a homogeneous mixture, pizza is a heterogeneous mixture, sand is a heterogeneous mixture, saltwater is a homogeneous mixture, bronze is a homogeneous mixture, milk is a homogeneous mixture, paint is a homogeneous mixture, air is a homogeneous mixture, soil is a heterogeneous mixture.

Step5: Analyze Part 4

Calcium is an element, hydrogen ($H_2$) is an element, orange juice with pulp is a heterogeneous mixture, baking soda ($NaHCO_3$) is a compound, helium is an element, limestone ($CaCO_3$) is a compound, salad dressing is a heterogeneous mixture, vinegar ($CH_3COOH$) is a compound.

Step6: Analyze Part 5

For the pictures:

• If all atoms are the same type and not bonded to different types, it's an element.
• If different types of atoms are bonded together, it's a compound.
• If there are different non - bonded elements, it's a mixture of elements.
• If there are different non - bonded compounds, it's a mixture of compounds.
• If there are both elements and compounds present, it's a mixture of elements and compounds.

Answer:

1. E. Element
2. E. Element
3. HE. Heterogeneous mixture
4. C. Compound
5. E. Element
6. C. Compound
7. HE. Heterogeneous mixture
8. C. Compound
9. E. Mixture of elements and compounds (assuming different types of atoms and bonded/non - bonded combinations)
10. B. Compound (all are the same type of compound)
11. A. Element (all are the same type of atom)
12. A. Element (all are the same type of diatomic molecule)
13. D. Mixture of compounds (different types of compounds)
14. E. Mixture of elements and compounds (different types of atoms and compounds)