Science Flashcards: Mixtures vs Compounds

Questions and Answers

What is the difference between a mixture and a compound?

A mixture is made of two or more substances that are not chemically combined, whereas a compound is made of two or more elements that are chemically combined.

The composition of a mixture can vary.

True

The composition of a compound can vary.

False

What is the difference between a compound and an element? Give two examples of each.

A compound is a combination of two or more elements that are chemically bound together. An element is just a single element. Examples: Sodium chloride (NaCl) is a compound, and iron (Fe) is an element. Signup and view all the answers

What is the difference between an atom and a molecule?

An atom is the smallest amount of an element, whereas a molecule is the smallest amount of a compound. Signup and view all the answers

What is the difference between a heterogeneous mixture and a homogeneous mixture? Give an example of each.

In a heterogeneous mixture, it is possible to see the various components. An example is sand in water. A homogeneous mixture looks like it is just one substance; an example is milk. Signup and view all the answers

What are three types of homogeneous mixtures? Give an example of each.

Solution: Kool-Aid powder dissolved in water; Suspension: Clay powder suspended in water; Colloid: Fog. Signup and view all the answers

Describe five physical properties of water.

Boiling point: 100°C, Odor: Odorless, Flammability: Nonflammable, Density: 1.00 g/cc, Color: Clear. Signup and view all the answers

How is density calculated? What are the units?

Density is calculated using the formula D = m/v; units are g/cc. Signup and view all the answers

What are the separation techniques of filtration and distillation?

Filtration requires one substance to be soluble in the liquid and one to be insoluble. Distillation requires one substance to have a different boiling point than the other. Signup and view all the answers

Explain the difference between a chemical change and a physical change.

In a physical change, the identity of the substance does not change; it simply changes form. In a chemical change, new substances with new identities and properties are created. Signup and view all the answers

What is a molecule?

The smallest unit of most compounds. Signup and view all the answers

What is a compound?

A substance formed by the chemical combination of two or more elements in definite proportions. Signup and view all the answers

What is a pure substance?

A substance with constant composition. Signup and view all the answers

What is an element?

Any substance that cannot be made smaller. Signup and view all the answers

What is an atom?

The smallest unit of an element. Signup and view all the answers

What is a heterogeneous mixture?

The parts of the mixture are noticeably different from one another. Signup and view all the answers

What is a homogeneous mixture?

A mixture that is the same throughout. Signup and view all the answers

What is a solution?

A homogeneous mixture of two or more substances. Signup and view all the answers

What is a suspension?

A heterogeneous mixture that separates into layers over time. Signup and view all the answers

What is a colloid?

A heterogeneous mixture whose particles never settle. Signup and view all the answers

What is a physical property?

A characteristic of a substance that can be observed without changing it into another substance. Signup and view all the answers

What is viscosity?

A liquid's resistance to flow. Signup and view all the answers

What is conductivity?

The ability of a material to allow either heat or electricity to flow through it. Signup and view all the answers

What is malleability?

The ability of a substance to be hammered or beaten into thin sheets. Signup and view all the answers

What is melting point?

The temperature at which a solid becomes a liquid. Signup and view all the answers

What is boiling point?

The temperature at which a substance changes from a liquid to a gas. Signup and view all the answers

What is density?

The amount of matter in a given space. Signup and view all the answers

What is characteristic property?

A property that always stays the same. Signup and view all the answers

What is filtration?

A method that separates mixtures based on the solubility of substances. Signup and view all the answers

Study Notes

Mixtures and Compounds

Mixtures consist of two or more substances that are not chemically combined, allowing variability in composition.
Compounds are formed from two or more elements chemically combined in fixed ratios, exemplified by water (H₂O).

Composition Variability

Mixtures can have changing compositions, demonstrated by the varying amounts of sugar in coffee.
In contrast, compounds maintain a constant composition, as seen in water consistently being H₂O.

Elements vs. Compounds

Compounds consist of multiple elements joined together; for example, sodium chloride (NaCl).
Elements are singular substances, like iron (Fe).

Atoms vs. Molecules

Atoms represent the smallest unit of an element, while molecules are the smallest unit of a compound, composed of atoms.

Types of Mixtures

Heterogeneous mixtures reveal their different components, such as sand in water.
Homogeneous mixtures appear uniform, such as milk or Gatorade.

Types of Homogeneous Mixtures

Solutions: Mixtures where substances are entirely dissolved, e.g., Kool-Aid.
Suspensions: Mixtures that can settle over time, like clay in water.
Colloids: Mixtures with particles that remain suspended, such as fog or homogenized milk.

Physical Properties of Water

Boiling point: 100°C
Odor: Odorless
Flammability: Nonflammable
Density: 1.00 g/cc
Color: Clear

Density Calculation

Density formula: D = m/v
Common units for density: g/cc

Separation Techniques

Filtration separates based on solubility; one substance is soluble while the other is not.
Distillation relies on differing boiling points of substances.

Changes in Substances

Physical changes do not alter the substance's identity, only its form.
Chemical changes produce new substances with distinct identities and properties.

Key Definitions

Molecule: Smallest unit of most compounds.
Compound: Substances formed by chemically combining two or more elements in specific proportions.
Pure Substance: Consistent composition without variation.
Element: Basic substance that cannot be reduced further.
Atom: The smallest unit of an element.

Mixture Classifications

Heterogeneous Mixture: Components are distinctly different.
Homogeneous Mixture: Uniform mixture throughout.
Solution: A type of homogeneous mixture.
Suspension: Heterogeneous mixture that separates over time.
Colloid: Heterogeneous mixture with non-settling particles.

Physical Properties

Physical property: Observable characteristics without altering the substance.
Viscosity: Resistance of a liquid to flow.
Conductivity: Material's ability to conduct heat or electricity.
Malleability: Capability of a substance to be shaped or thinned out.
Melting Point: Temperature where solid transitions to liquid.
Boiling Point: Temperature where liquid changes to gas.
Density: Mass of a substance in a given volume.
Characteristic Property: Consistent property unique to a substance.

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Explore the fundamental differences between mixtures and compounds with these flashcards. Learn how their compositions vary and understand their chemical properties. Perfect for science students looking to solidify their knowledge of basic chemistry concepts.