Chemistry chapter 1: states of matter

What are atoms

atoms are submircoscopic particles that are the fundamental building blocks of ordinary matter.

Free atoms are rare in nature; instead they bind together geometrical arrangements for form

Molecules

What is an example of free atoms bonding together to form a molecule

A water molecule

A water molecule is composed of

once oxygen and 2 hydrogen atoms

What is a hydrogen peroxide molecule made up of

two hydrogen atoms and two oxygen atoms

Hydrogen peroxide is what kind of liquid

Unstable

Water is what kind of liquid

Stable

The definition of chemistry

Chemistry- is the science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules.

Graphite and diamond are both composed of exactly the same

atoms (carbon), but they have different structures.

In graphite the atoms are arranged in

sheets, but the sheets arent tightly bound together

The graphite sheets allow for

them to slide past eachother

In diamonds the carbon atoms are all bond together, resulting in nearly unbreakable layers.

this arrangement gives diamond its exceptional hardness and high melting point.

Who is Antoine Lavoisier?

A French chemist known as the "Father of Modern Chemistry." He established the law of conservation of mass and named oxygen and hydrogen.

What is a hypothesis

A tentative interpretation or explanation of the observations. It is a testable statement that can be supported or refuted through experimentation.

How did Lavoisier execute his hypothesis in his research?

He explained his observations on combustion by hypothesizing that when a substance burns, it combines with a component of air.

A good hypothesis is

Falsifable

What is an experiment?

Highly controlled procedure designed to generate observations that confirm or refute hypothesis.

What is a scientific law,

A brief statement that summarizes past observations on combustion with the law conservation of mass.

The law of conservation of mass states

“In a chemical reaction, matter is neither created nor destroyed.

What is a scientific theory?

Is a model for the way nature is and tries to explain why things happen based on extensive evidence and experimentation.

What is a good example of scientific theory

the atomic theory by John dalton.

what is the difference between a law and a theory?

A law summarizes a series of related observations; a theory gives underlying reasons for them.

What is matter?

Anything that occupies space and has mass

What do you call a specific instance of matter-such as air, water or sand?

a substance

How do we classify matter?

According to its state, (physical form) and its composition (the basic components that make it up)

What are the three states of matter

Solid, liquid, and gas.

How does a state of matter change from solid to liquid

with increasing temperature

Glass and other amorphous solids can be thought of

intermediate between solids and liquids, they do not have distinct melting points

In solid matter

atoms or molecules pack closely to each other in fixed locations, they vibrate but don’t move around or past each other.

A solid has what kind of shape?

rigid shape and a fixed volume

What are some examples of solids

aluminum and diamond as well as ice and wood.

Solid matter can be

crystaline, atoms or molecules are in patterns.

Solid matter can also be

amorphous, where atoms or molecules are arranged randomly.

table salt and diamond are examples of

crystalline solids characterized by a regular repeating arrangement of atoms.

Glass and plastic are

examples of amorphous solids, lacking a defined geometric structure.

I liquid matter, atoms or molecules pack as closely as they do in solid matter, but they are free to move relative to each other

true

Do liquids assume the shape of their containers?

yes, liquids take the shape of their containers while maintaining a constant volume.

Water, alcohol and gasoline are all

substances that are liquids at room temperature

In gaseous matter

atoms or molecules have a lot of space between them and are free to move relative to one another, making gas compressible.

Gases always

assume the shape and volume of their containers.

Substances that are gases at room temperature are

helium, nitrogen, carbon dioxide

The first division in the classification of matter is between a

pure substance and a mixture

A pure substance is made up of

only one component, it’s composition is invariant (doesnt vary from one sample to another)

Helium, water and table salt are

all pure substances

The components of a pure substance can be individual atoms or groups of atoms joined together

true

A mixture is

composed of two or more components in proportions that can vary from one sample to another

Sweetned tea is an example of

a mixture because the components, water and sugar, can vary in ratio.

We can categorize pure substances into two types

elements and compounds- depending on whether or not they can be broken down into simpler substances

Helium is a pure substance but is also a good example of an

element, as it cannot be broken down into simpler substances and is one of the fundamental building blocks of matter.

Water, also a pure substance, is a good example of an

compound, a substance made of two or more elements

Mixtures are categorized into two types

heterogenous and homogeneous, based on the uniformity of their composition.

Wet sand is an example of a

heterogenous mixture the compostions varies from one region of the mixture to another.

Sweet tea is what kind of mixture

homogenous one with the same composition throughout

Homogenous mixtures have uniform compositions because

the atoms or molecules that compose them mix uniformly.

Heterogenous mixtures are made up of distinct regions because

the atoms or molecules that compose them are separate.

We can seperate a mixture of sand and water by

Decanting, carefully pouring off- water into another container

Homogenous mixtures can be seperated by

by distillation, a process in which the mixture is heated to boil off the more volatile (easy vaporizable) liquid. This method evaporates the liquid and then condenses it back into a liquid, leaving the non-volatile components behind.

If a mixture is composed of an insoluble solid and a liquid, we can seprate the two by

filtration, the mixture is poured through a filter in a paper in a funnel.

Changes that alter only state or appearance, but not composition are

Physical changes

The atoms or molecules that compose a substance

do not change their identity during a physical change

What makes water boiling a physical change?

During boiling, water changes from liquid to gas, but its molecular structure (H₂O) remains unchanged.

Changes that alter the composition of matter are

Chemical changes

During a chemical change

atoms rearrange, transforming the original substances into different substances

Rusting is an example of

a chemical change where iron reacts with oxygen to form iron oxide.

A physical property is

A property that a substance displays without changing it’s composition

A chemical property is

is a property that a substance displays only by changing its composition via a chemical change.

The smell of gasoline is a

physical property, gasoline doesnt does not change its composition when it exhibits its odor.

The flammability of gasoline is

is a chemical property, gasoline changes its composition when it burns, turning it into completely new substances.

Physical properties include

odor, taste,color, appearance, melting point, boiling point, and density. They can be observed without changing the substance's composition.

Chemical properties include

corrosiveness, flammability, acidity, toxicity

Vaporization is what kind of change

physical change, the molecules remain the same before and after the change

What is the scientific definition of energy?

The capacity to do work

What is the definition of work

The action of a force through a distance resulting in energy transfer.

The total energy of an object is a sum of

its kinetic energy (the energy associated with its motion) and potential energy (the energy stored due to its position).

An example of potential energy conversion

A box gets dropped, the weight turns into kinetic energy and when it hits the ground it turns into thermal energy

What is thermal energy

The energy associated with the temperature of an object that results from the kinetic energy of its particles. It is a form of energy that can be transferred as heat.

Write out thermal energy equation

yes (potential energy = Initial- final potential energy of the weight

The idea that energy is neither created nor destroyed is known as?

the law of conservation of energy.

the total quantity of energy does not change

it remains constant

What type of energy is chemical energy?

Chemical energy is a form of potential energy stored within the bonds of chemical compounds. It can be released during chemical reactions.

Objects or systems with high potential energy tend to be

Unstable, stable when it releases energy or when it drops for better reference in a state of lower potential energy.

Gasoline undergoing chemical changes lowers their

Potential energy, usage like combustion (putting to work lower potential energy)

Energy is always conserved in a physical or chemical change

it is neither created nor destroyed

Systems with high potential eneergy tend to change in ways that lower their potential energy

transferring energy to the surroundings

What is the meter

the standard unit of length

What is the kilogram

the standard unit of mass

The second is

the standard unit of time

The kelvin is

the standard unit of temperature

The meter is slightly longer than a yard, what is a meters dimensions and a yards

1 yard= 36 inches 1 meter is 39.37inches