Chemistry Test #1

THE PARTICLE MODEL OF

MATTER

All matter is made up of extremely tiny

particles.

Each pure substance has its own kind of

particle, different from the particles of other

pure substances.

Particles attract each other.

Particles are always moving.

Particles at a higher temperature move faster

on average than particles at a lower

temperature.

The ways we classify matter and what they are

According to its state as a gas, a liquid, or

a solid

According to its composition as a mixture

or a pure substance

Mixtures can be classified by their

properties

If the particles are uniformly scattered, the

mixture is homogeneous

If the particles are NOT uniformly scattered, the

mixture is heterogeneous

what are chemical and physical properties

Physical Properties-

Any property that can be observed or measured

without forming a new substance

Chemical Properties-

Any property that describes how a substance

reacts with another substance when forming a

new substance

Qualitative physical properties?

A qualitative physical

property is a

characteristic of a

substance that can be

described but might

not be measured ex Colour

Texture

Taste

Smell

State

Crystal shape

Malleability

Ductility

Quantitative physical properties?

A quantitative

physical property is a

characteristic of a

substance that can be

measured numerically ex Melting temperature

Boiling temperature

Density

Viscosity

Solubility

Electrical

conductivity

Heat conductivity

Hardness

What are chemical properties ( add examples)

Any property that

describes how a substance

reacts with another

substance when forming a

new substance is a

chemical property ex Reacts with water

Reacts with air

Reacts with pure

oxygen

Reacts with acids

Reacts with other pure

substances

Toxicity

Combustibility

Stability

2 ways used to classify changes of matter and what they mean

Physical Changes-

A substance changes in form but not in chemical

composition; no new substances are formed ex. Ice melting/freezing

The taste of chlorinated

water

Tearing a sheet of paper

Chemical Changes-

Causes one or more new substances to be

formed; may be difficult or impossible to reverse ex. Burning paper

Heating mercury oxide

Rusting

Digestion

Baking/Cooking

exothermic reactions

A reaction that releases energy in the form of heat. The energy is released because the energy required to break the bonds in the reactants is less than the energy released when new bonds are formed in the products. Examples include combustion, explosions, and nuclear fission.

Endothermic Reactions

A reaction that absorbs energy from its surroundings, usually in the form of heat. In these reactions, the energy required to break the bonds in the reactants is greater than the energy released when new bonds are formed in the products. Examples include photosynthesis, melting ice, and dissolving ammonium chloride in water.

Precipitate:

A solid that forms when two non-solid (liquid or gas) substances are combined, which

indicates that a chemical reaction has occurred.

Pure Substance

Matter that has a certain set of physical and chemical properties and certain chemical

composition that sets it apart from any other type of matter.

Element:

A substance that cannot be broken down into any simpler substance.

Compound:

Two or more elements combined chemically in fixed proportions.

Mixture:

A combination of pure substances not combined chemically.

Mechanical Mixture:

A mixture whose individual components are visible within it.

Solution:

A mixture whose individual components are not visible within it.

Metals

shiny, malleable, ductile, conduct electricity, are solid at room temperature (except mercury)

and have high melting and boiling points.

Non-metals

are solid, liquid, or gas at room temperature, have low melting and boiling points, are dull,

brittle and do not conduct electricity (insulators).

Alkali metals

These are the most reactive metals, and many are so reactive that they require special storage.

Hydrogen is included in group 1 because of its atomic structure, but most modern periodic tables have it

disconnected from the periodic table. Hydrogen has many unique properties unlike any other, but is still

very violently like all of the other elements in group 1.

Alkaline Earth metals

Alkaline Earth metals react vigorously with some substances, but are not as reactive as the alkali metals.

Halogens

These are the most reactive non-metals, and react vigorously with almost every other element.

Noble gases

Noble gases are so un-reactive, that they will not chemically react with any other element.

Ion charge

Ion:

An electrically charged atom.

Oxidation Reaction:

A chemical reaction that requires oxygen (oxygen is a reactant).

Combustion:

A highly exothermic combination of a substance with oxygen, which requires oxygen and

some sort of fuel.

Corrosion:

A slow chemical reaction that occurs when oxygen and moisture combine with a substance

(usually a metal) to decompose (eat away) at that substance.

Cellular Respiration:

A chemical reaction that takes place in the cells in your body, when glucose (from food)

reacts with oxygen to produce energy, water, and carbon dioxide.

Factors affecting reaction rate

1. The concentration of reactants- So the greater the concentration, the faster a reaction occurs. Increased concentration of the reactants means there are more atoms of each reactant available to react 2. The temperature of reactants. The more heat added to the reactants, the faster the reaction. The added heat causes the atoms of each reactant to move faster, increasing chances of collision. Lastly, the surface area of reactants. 3. Increasing the surface area increases rate of reaction. Greater surface area of reactants means more area is available for the reaction. 4. Agitatiion -The mixing of reactants by shaking or stirring.

Agitation increases the chances of reactants colliding with each other. 5. Electrical energy - Electrical energy (electricity) can be used to speed up certain types of chemical reactions or make chemicals

react in a way they wouldn’t otherwise act if the electrical energy were not present.

Electrolysis

The use of electrical energy to break down substances.

What is the law of conservation of mass

The total mass of the product(s) is EQUAL to the total mass of the reactants.

In a chemical reaction, products are formed when the reactants undergoes a change. These products usually

look very different from the reactants. However the total mass of the product(s) always equals the original mass

of the reactants, because matter is not created or destroyed in a chemical reaction.

Closed and open systems for a chemical reaction

Closed System: A system in which mass or energy (heat) cannot be lost to or gained from the environment.

Open Systems: A system in which mass or energy (heat) can be lost to or gained from the environment.

What are compounds

Compounds result when two or more elements combine chemically in specific, fixed proportions (such as H20).

Compounds can be further classified based on which of the elements they are made of.

What are ionic compounds

One (or more) metal ion(s) combining with one (or more) non-metal ion(s), due to the

opposite charges of the ions, forming an extremely strong bond between the ions.

 Are a combination of positive and negative ions,

 Have extremely strong bonds,

 Have high melting and boiling points,

 Are solids at room temperature,

 Conduct electricity,

 Form distinct crystal shapes.

explanation: When an element gains electrons it will form a negatively charged ion. Chlorine gains one electron when it

forms an ion and becomes Cl-

. When an element loses electrons it becomes positively charged. Sodium loses an

electron when it forms an ion and becomes Na+

. Opposite charges will be attracted to each other, much like

magnets. When a Na+

ion and a Clion combine they form an electrically neutral substance of NaCl (otherwise

known as table salt). The combining of ions with opposite charges results in a very strong bond between them.

Molecular compound

(Molecule) The combination of two or more non-metals.

 Are a combination of elements not in their ion form,

 Have bonds that are relatively weak,

 Have relatively low melting and boiling points,

 Can be solids, liquids, or gases at room temperature,

 Are poor conductors or non-conductors (insulators) of electricity,

 Rarely form crystals when in their solid form.

Diatomic Molecules:

Compounds made up of two atoms (often the same two atoms and are all gases at room

temperature).

Ion

atom or molecule that has lost or gained one or more of its valence electrons