Question

classification of matter worksheet
part 1: classify each of the following substances as: pure substance (an element, or compound) or mixture (homogeneous mixture (solution), or a heterogeneous mixture)

1. sand
2. salt (nacl)
3. pure water (h₂o)
4. soil
5. soda
6. pure air
7. carbon dioxide (co₂)
8. gold
9. bronze
10. oxygen
11. salad dressing
12. salt water

part 2:
sample pure substance or mixture element, compound, heterogeneous mixture or homogeneous
sugar (c₆h₁₂o₆) mixture
alcohol (100%) pure substance
coffee mixture
pebbles and marbles mixture
salt and pepper mixture
sugar in hot water
baking soda (nahco₃)
mercury (hg)
oil water
jam
paint
part 3: questions: answer these questions on a separate sheet of paper.

1. list the 5 main ideas of the particle theory.
2. use the particle theory to explain why water changes from a solid to a liquid when it is heated.
3. give three examples of a pure substance.
4. give three examples of a mixture.
5. describe a solution.
6. compare the similarities and differences between a mechanical mixture and a solution. use a venn - diagram.

Explanation:

Step1: Recall matter - classification rules

Pure substances are either elements or compounds. Mixtures are combinations of substances. Homogeneous mixtures (solutions) have uniform composition, and heterogeneous mixtures have non - uniform composition.

Step2: Classify substances in Part 1

• Sand: Heterogeneous mixture (contains different particles like silica, minerals etc.).
• Salt (NaCl): Pure substance, compound.
• Pure Water (H₂O): Pure substance, compound.
• Soil: Heterogeneous mixture (contains minerals, organic matter etc.).
• Soda: Homogeneous mixture (solution of carbon dioxide, sugar etc. in water).
• Pure Air: Homogeneous mixture (contains nitrogen, oxygen etc. in fixed proportions).
• Carbon Dioxide (CO₂): Pure substance, compound.
• Gold: Pure substance, element.
• Bronze: Homogeneous mixture (alloy of copper and tin).
• Oxygen: Pure substance, element.
• Salad Dressing: Heterogeneous mixture (oil, vinegar, herbs etc. separate over time).
• Salt Water: Homogeneous mixture (solution of salt in water).

Step3: Classify substances in Part 2

• Sugar (C₆H₁₂O₆): Pure substance, compound.
• Alcohol (100%): Pure substance, compound.
• Coffee: Homogeneous mixture (solution of caffeine, acids etc. in water).
• Pebbles and Marbles: Heterogeneous mixture.
• Salt and Pepper: Heterogeneous mixture.
• Sugar in hot water: Homogeneous mixture (solution).
• Baking soda (NaHCO₃): Pure substance, compound.
• Mercury (Hg): Pure substance, element.
• Oil water: Heterogeneous mixture (oil and water don't mix).
• Jam: Heterogeneous mixture (contains fruit pieces, sugar etc.).
• Paint: Heterogeneous mixture (pigments in a liquid medium).

Step4: Answer Part 3 questions

1. The 5 main ideas of the particle theory:

• All matter is made up of tiny particles.
• The particles are in constant motion.
• There are spaces between the particles.
• Different substances are made up of different kinds of particles.
• The particles are held together by forces of attraction.

1. When water is heated, the heat energy causes the particles of ice (solid water) to gain kinetic energy. The increased kinetic energy overcomes the forces of attraction holding the particles in a fixed, orderly arrangement in the solid state. The particles start to move more freely and the water changes to a liquid state.
2. Three examples of pure substances: Gold (element), Water (compound), Sodium Chloride (compound).
3. Three examples of mixtures: Soil, Salad Dressing, Pebbles and Marbles.
4. A solution is a homogeneous mixture in which one or more substances (solutes) are dissolved in another substance (solvent). The solute particles are very small and evenly distributed throughout the solvent.
5. In a Venn - diagram:

• Similarities: Both are mixtures, i.e., made up of two or more substances.
• Differences: A mechanical mixture (heterogeneous mixture) has a non - uniform composition and the components can be seen or separated easily (e.g., pebbles and marbles). A solution (homogeneous mixture) has a uniform composition and the solute particles are too small to be seen and cannot be separated easily by physical means like filtration.

Answer:

Part 1:

1. Heterogeneous mixture
2. Pure substance, compound
3. Pure substance, compound
4. Heterogeneous mixture
5. Homogeneous mixture
6. Homogeneous mixture
7. Pure substance, compound
8. Pure substance, element
9. Homogeneous mixture
10. Pure substance, element
11. Heterogeneous mixture
12. Homogeneous mixture

Part 2:

1. Pure substance, compound
2. Pure substance, compound
3. Homogeneous mixture
4. Heterogeneous mixture
5. Heterogeneous mixture
6. Homogeneous mixture
7. Pure substance, compound
8. Pure substance, element
9. Heterogeneous mixture
10. Heterogeneous mixture
11. Heterogeneous mixture

Part 3:

1. All matter is made up of tiny particles; The particles are in constant motion; There are spaces between the particles; Different substances are made up of different kinds of particles; The particles are held together by forces of attraction.
2. Heat energy gives particles kinetic energy to overcome forces of attraction in solid state and move more freely as a liquid.
3. Gold, Water, Sodium Chloride.
4. Soil, Salad Dressing, Pebbles and Marbles.
5. A homogeneous mixture where solutes are dissolved in a solvent with evenly - distributed small solute particles.
6. Similarities: Both are mixtures. Differences: Mechanical mixtures are non - uniform and components are easily separable; solutions are uniform and components are not easily separable.