Chapter 3: Matter and Energy

Physical processes

________ can be used to separate mixtures because there are no chemical interactions between the components.

Carbohydrates

________ are the primary fuel for the body.

Matter

Anything that has mass and occupies space

Pure Substances

A matter that has a fixed or definite composition

Element

The simplest type of pure substance

Atoms

These are extremely tiny particles that make up each type of matter

Compound

A pure substance that consists of atoms of two or more elements, always chemically combined in the same proportion

Bonds

Happens when atoms are held together by attractions

Molecules

Small groups of atoms

Homogenous Mixture

Also called a solution, the composition is uniform throughout the sample

Heterogeneous Mixture

The components do not have a uniform composition throughout the sample

Filtration

It helps in separating solids from liquids, which involves pouring a mixture through a filter paper set in a funnel

Chromatography

Different components of a liquid mixture separate as they move at different rates up the surface of a piece of chromatography paper

State of Matter

The physical forms of matter

Solid

It has a definite shape and volume

Liquid

It has a definite volume, but not a definite shape

Gas

It does not have a definite shape or volume

Physical properties

These are those characteristics that can be observed or measured without affecting the identity of a substance

Chemical properties

These are those that describe the ability of a substance to change into a new substance

Degrees

Smaller units of temperature

Kelvins (K)

The unit of Kelvin Scale, no degree symbol is used

Energy

The ability to do work

Kinetic Energy

The energy of motion

Potential Energy

Determined by the position of an object or by the chemical composition of a substance

Heat

The energy associated with the motion of particles

Joule (J)

The SI unit of energy and work

Calorie (cal)

Defined as the amount of energy needed to raise the temperature of 1 g of water by 1 °C

Specific Heat

The amount of heat needed to raise the temperature of exactly 1 g of a substance by exactly 1 °C

Heat Equation

Specific heat expression that is arranged to solve for heat

Change of State

It occurs when the matter is converted from one state to another

Melting Point

The particles of a solid gain sufficient energy to overcome the attractive forces that hold them together

Freezing Point

Occurs when a liquid changes to a solid

Heat Fusion

The energy that must be added to convert exactly 1 g of solid to liquid at the melting point

Evaporation

It is taking place as water molecules with sufficient energy escape from the liquid surface and enter the gas phase

Boiling Point (bp)

The molecules within a liquid have enough energy to overcome their attractive forces and become a gas

Condensation

The water vapor is converted back to liquid as the water molecules lose kinetic energy and slow down

Sublimation

The particles on the surface of a solid change directly to a gas with no temperature change and without going through the liquid state

Deposition

The reverse of sublimation; the gas particles change directly to a solid

Freezer Burn

This occurs when a solid is left in the freezer for a long time, and so much water sublimes that solids become dry and shrunken

Heat of Vaporization

The energy that must be added to convert exactly 1 g of liquid to gas at its boiling point

Cooling Curve

A diagram of the cooling process in which the temperature decreases as heat is removed

calorimeter

In the nutrition laboratory, foods are burned in a _______ to determine their *energy value.*

energy values

The _____ for food are the kilocalories or kilojoules obtained from burning 1 g of carbohydrate, fat, or protein.

Specific Heat Formula