Matter and Changes Review Guide - Video Notes

A set of practice flashcards covering definitions of matter, mixtures, phases, lab techniques, and common questions from the lecture notes on Matter and Changes.

What is a pure substance?

Matter with definite and uniform composition.

What is a mixture?

A physical blend of two or more substances.

What does homogeneous mean?

Uniform composition.

What does heterogeneous mean?

Non-uniform composition.

What is a chemical change?

A process where a substance transforms into a new substance.

What is a physical change?

A change where the composition stays the same.

Is Aluminum sulfide (Al2S3) a pure substance or a mixture?

Pure substance; it is a compound.

Is soil a pure substance or mixture, and is it homogeneous or heterogeneous?

Mixture; heterogeneous.

Is carbon monoxide (CO) a pure substance or mixture?

Pure substance; compound.

Is carbon dioxide (CO2) a pure substance or mixture?

Pure substance; compound.

Is sugar (C6H12O6) a pure substance or mixture?

Pure substance; compound.

Is air a pure substance or mixture, and is it homogeneous or heterogeneous?

Mixture; homogeneous.

Is water a pure substance or mixture?

Pure substance; compound.

Is magnesium (Mg) an element, a compound, homogeneous, or heterogeneous?

Element.

Is manganese (Mn) an element, a compound, homogeneous, or heterogeneous?

Element.

Is ammonia (NH3) an element, a compound, homogeneous, or heterogeneous?

Compound.

What does (aq) indicate?

Aqueous; dissolved in water.

Which substance cannot be decomposed by physical or chemical means?

Elements.

Which lab process separates liquids with different boiling points?

Distillation.

Which lab process separates a solid from a liquid?

Filtration.

A chemical formula represents a compound or an element?

Compound.

What does the Law of Conservation state?

Matter cannot be created or destroyed.

Which substances can be broken down chemically and why: C, Cu, CO2, CuO?

CO2 and CuO can be broken down chemically because they are compounds; C and Cu are elements.

What is sublimation?

Phase change from solid to gas with no liquid phase.

List all phase changes and their names.

Melting (solid to liquid), Freezing (liquid to solid), Evaporation/Boiling (liquid to gas), Condensation (gas to liquid), Sublimation (solid to gas).

What is the density of a board with mass 28.6 g and dimensions 5.54 cm × 10.6 cm × 1.99 cm?

Approximately 0.245 g/cm³.

CaCl2 has density 2.50 g/mL. What is the mass of 15.0 L of this substance?

37,500 g (37.5 kg).

A metal weighs 25.0 g. It is placed in a graduated cylinder with 25.0 mL of water; volume rises to 37.0 mL. What is the density of the metal?

Approximately 2.08 g/mL.

In the separating mixtures lab, what will be in the bottom beaker after filtering sand and salt water?

Salt water.

How would you recover salt from a mixture of salt and water?

Evaporate the water to leave the salt behind.

What are the four signs of a chemical change?

Formation of gas, formation of a precipitate, energy change, color change.