Chemistry Notes Review - Observations, Particle Theory, Classification of Matter, and Physical Properties

A set of QUESTION_AND_ANSWER flashcards covering observations (qualitative vs quantitative), lab reports, the Particle Theory of Matter (states and changes), classification of matter (elements, compounds, mixtures), physical properties, observations vs inferences, and data presentation.

What is the difference between qualitative and quantitative observations?

Qualitative observations describe qualities using the senses (color, texture, smell, etc.) and are non-numeric. Quantitative observations involve measurements and numbers (mass, length, temperature).

Give an example of a qualitative observation.

The plant color is green.

Give an example of a quantitative observation.

The plant grew 5 cm in one week.

What are the typical sections of a lab report?

Problem/Purpose, Hypothesis, Materials, Procedure, Observations/Results, Conclusion, and Discussion.

List the five statements of the Particle Theory of Matter.

1) Matter is made of tiny particles. 2) Particles are in constant motion. 3) The particles of a substance are different from those of other substances. 4) There are spaces between particles. 5) The strength of the attractive forces between particles and their energy/motion depend on temperature.

Describe the solid state in the Particle Theory.

Particles are tightly packed with small spaces, strong attractions, move slowly, energy level is low.

Describe the liquid state in the Particle Theory.

Particles are less tightly packed with moderate spaces, moderate attractions, move faster, energy level higher than in a solid.

Describe the gaseous state in the Particle Theory.

Particles are far apart with large spaces, weak attractions, move rapidly, energy level is high.

What happens to particle energy and spacing during melting?

Energy increases, spaces between particles increase, attractive forces weaken; solid becomes liquid.

What happens to particle energy and spacing during freezing?

Energy decreases, spaces between particles decrease, movement slows; liquid becomes solid.

What happens during evaporation/boiling?

Energy increases; particles escape from liquid to gas; spaces between particles increase; movement becomes faster.

What happens during condensation?

Gas to liquid; energy decreases; particles come closer and move slower.

What happens during sublimation?

Solid to gas; energy increases; particles move faster and overcome attractions.

What is a pure substance?

Matter with fixed composition that cannot be broken down by physical means; includes elements and compounds.

What is an element?

A pure substance made of one type of atom; cannot be broken down into simpler substances by chemical means.

What is a compound?

A pure substance formed when two or more elements are chemically combined in fixed proportions.

What is a mixture?

Matter containing two or more substances that retain their own properties and can be separated by physical methods.

What is a homogeneous mixture?

Uniform composition; appears as one phase (e.g., sugar water, air).

What is a heterogeneous mixture?

Non-uniform composition; distinct phases are visible (e.g., sand and water).

Is water a compound or element?

Water is a compound (H2O).

Is table salt (NaCl) a compound or element?

Table salt is a compound (sodium chloride).

Is sugar in water a pure substance or a mixture?

A mixture (a homogeneous solution).

What is a physical property?

A characteristic that can be observed or measured without changing the substance’s identity (e.g., color, density, melting point, state).

What is a qualitative physical property?

Observed properties such as color or odor; not measured with numbers.

What is a quantitative physical property?

Measured properties such as mass, volume, density, temperature.

What is an observation vs. an inference?

Observation is what you directly perceive with senses or instruments. An inference is a conclusion drawn from observations and prior knowledge.

Why are graphs useful for presenting quantitative data?

Graphs organize data visually, reveal trends, and make comparisons easier.

How does temperature relate to particle energy and movement in the Particle Theory?

Higher temperature increases particle energy and movement; lower temperature decreases them.

What is the role of spaces between particles in matter?

The size of spaces between particles helps determine the state of matter; solids have small spaces, gases have large spaces, affecting how particles move and interact.