chemistry chapter 1

pure substances

(all ____ are homozygous) it has a fixed composition (every sample of a pure substance has the same physical/chemical properties. these properties are so specific they can be used to identify the substance. in contrast the properties of a mixture depend on the relative amount of the mixtures components. they represent a blend of the properties of each component) (every sample of a pure substance has exactly the same composition) (ex: gold)

elements

(all the matter that people have observed is made of certain building blocks called elements) is a pure substance that cannot be broken down into simpler, stable substances (all elements are only one type of atom)

mixtures

(in contrast to pure substances) is a blend of two or more kinds of matter, each of which keep their identity and properties. sometimes two samples from the same mixture will be different (ex: rock because it is usually a mixture of smaller minerals) (most things are mixtures)

all chemicals are a little impure (different companies have different standers)

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any sample of matter can be classified as a pure substance or a mixture a pure substance can either be an element or a compound. it is the same throughout with no variation

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copper is a typical type of metal it is solid at room temp, it is malleable, ductile, and can conduct electricity. copper is an essential mineral in the human diet

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every physical and chemical change requires energy. the energy can take several forms: light/heat. the amount of energy helps determine what type of change takes place

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metals can become a better conductor of electricity as temperature decreases.

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phosphorus is one of the five solid nonmetals. there are two types of phosphorus: red (which is red powder) and white (a waxy solid and is stored underwater because it ignites in air) all living things contain phosphorus

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pure substances are either compounds or elements. a compound can only be broken down into two or more simpler compounds or elements by a chemical change. in contrast a mixture can be separated by the use of physical properties

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the parts of mixtures can be separated using the differences in properties of the substances making up the mixture enables the separation (ex: filters by using the property of a particle size) (can also separate mixture by centrifuges/chromatography)

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what groups in the periodic table are composed entirely of metals?

1-12

physical change

a change in a substance that does not involve a change in the identity of the substance (grinding, cutting, melting/boiling)

chemical reaction

a change in which at least one new substance is formed is called a chemical reaction (often represented as an equation) (chemical reactions do not affect the total amount of matter present before and after the change. the amount of matter, and therefor the mass remains the same)

what is mass

a large body of matter with no definite shape

how does a liquid differ from a gas

a liquid has a definitive volume and gas does not have a definite volume

compare and contrast the poperties of a metal spoon and a plastic spoon. name three properties that are similar and 3 that are different.

a metal spoon is shiny, malleable, and conductive plastic spoon is not shiny, not malleable, and not conductive. they are both used for eating, they are both circular, and concaved and they both have handles

homogeneous

a mixture is called _____ if it is uniform in composition. in other words it looks the same throughout the whole mixture (often it is hard to even tell it is a mixture) (ex: water)

heterozygous

a mixture that is not uniform throughout. (ex: clay and water because clay goes sinks to the bottom so a sample from the bottom will be different from the top)

define property?

a quality, attribute, or characteristic of something

how does a solid differ from a liquid

a solid has a definite shape and volume and a liquid only has a definite volume

what is volume

an amount of space that an object takes up

what is meant by the word chemical, as used by scientists?

any pure substance with a definite composition

either basic research, applied research, or technological development a new type of refrigerant is developed a new element is synthesized in a particle accelerator a computer chip is redesigned to increase computers speed

applied basic tech

propeties

are used to distinguish between different substances and helps identify new substances. also used them to separate different substances that are mixed together

compare and contrast basic research, applied research, and technological development

basic research is research of basic info. applied research takes the basic info and creates new developments. tech research is creating new products with the info in the basic research/applied research

why is boiling a pot of water an example of a physical change

because the identity of the water doesnt change

compound

can be broken down into simpler, stable substances. it contains atoms of two or more elements that are chemically bonded (ex; water)

physical property

can be observed/measured without changing the identity of the substance (boiling point)

is cooking an egg a chemical change or physical

chemical because the substance is changing

define chemical property and list two examples of chemical properties

chemical properties: a substances ability to change into a different substance ex: rust on metal, milk souring, and sugar turning into caramel

what is the difference between a compound and a mixture

compounds require different materials

solid

definite shape and volume (ex: coal keeps its shape/size no matter the container it is in) (the particles are tight. they cannot move but they can vibrate back and forth) (the particles are held together because they are attracted to each other)

extensive properties

depend on the amount of matter that is present (the volume of an object is an example because it changes when materials are added to or taken away from) (it includes the volume, mass, and amount of energy in an object)

intensive properties

do not depend on the amount of matter present (ex: melting, boiling point, and density) (intensive properties are the same for two samples of a substance even if the samples are different in size)

list words that indicate the typical properties of metals

electrical conductor, malleable, ductile, tensile, and shiny

suppose element X is a poor conductor of heat and breaks when hit with a hammer. element Z is a good conductor of electricity and heat

element X is right element Z is left

the law of conservation of energy

even if some of the energy has changed form, the total energy system remains the same (in every case they have found that the total amount of energy present before the change is also present after the change. energy can be absorbed or released by one of the substances tho

what is the difference between extensive and intensive properties

extensive properties depend on the amount of matter is in an object and intensive properties do not

list the three common states of matter in order from the state with the fastest moving particles to the state with the slowest moving particles

gas, liquid, solid

liquids

has a definite volume but not shape (liquids assume the shape of their containers) (the particles in liquids are close together but they slide past one another) (the attractive forces do not work in liquids because the particles move more rapidly)

gas

has no definite shape or volume (ex: oxygen gas fills any container and takes the shape of the container) (the particles in gasses move really fast so the attractive forces can't keep them together)

metalloid

has some characteristics of metals and some of nonmetals. they are found in between the metals and nonmetals. they are all solids at room temp. they tend to be less malleable than metals but not as brittle as nonmetals. they are also semiconductors of electricity

matter

has two properties: it takes up space and has mass. everything has matter (all matter has volume)

solutions

homogenous mixtures are called ___

FE N CA HG

iron nitrogen calcium mercury

chemical change

is a change in which one or more substances are converted into different substances

metal

is an element that is a good electrical conductor and a good heat conductor (at room temp most metals are solids) (most metals are malleable which means they can be rolled into thin sheets) (they are also ductile which means they can be drawn into fine wire) (metals have strong tensile shape, which is the ability to resist breaking when pulled) (although metals share these properties they are different. mercury is liquid at room temp)

nonmetal

is an element that is a poor conductor of heat and electricity. (the periodic table has more metals than nonmetals) (many nonmetals are gasses at room temp) (they tend to be brittle rather than ductile) (bromine is a liquid at room temp) (carbon is a solid at room temp) (oxygen is a gas at room temp)

chemical

is any substance with a definite shape (sugar is a chemical and one unit of sucrose found in sugar cane is exactly the same as one unit of sucrose found anywhere else)

mass

is the measure of the amount of material that makes up an object or substance. you can measure mass by balance. the mass of matter will always measure greater than zero because mass is a necessary property of matter

molecule

is the smallest unit of a compound or element that retains all the properties of the compound or element

atom

is the smallest unit of an element that maintains a chemical identity of that element

chemistry

is the study of structure and properties of matter, the processes that matter undergoes and the energy changes that accompany these processes (a chemist studies matter)

is a substance that a filter can seperate into two parts a mixture or a pure substance? explain

it is a mixture because pure substances cannot be seperated (compounds/elements are pure substances)

what is chemistry?

it is a type of science that deals with the things that are composed with matter, and the processes matter undergoes

if you find an element in nature in its pure elemental state, what can you infer about the elements chemical reactivity? how can you tell that the element is a metal or nonmetal

it is going to be a non metal and probably a noble gas

a copper wire can conduct electricity whether the wire is very thin or thick. is electrical conductivity an extensive or intensive property

it is intensive

an unknown element is shiny and is found to be a good conductor of electricity. what other properties would you predict for it

malleable and ductile

the periodic table is broken up into two main groups

metals and nonmetals (metals-left and nonmetals- right)

describe the main differences among metals, nonmetals, and metalloids

metals are conductors, malleable, and ductile nonmetals are not conductive, brittle, and are mostly gasses metalloids are kinda shiny and unreactive

how does the composition of a pure substance differ from that of a mixture?

mixtures can be separated and compounds cannot

contrast mixtures with pure substances

mixtures can be seperated and pure substances cant

what group of elements do the noble gasses belong: metals, nonmetals, or metalloids?

nonmetal because they are gasses. gasses are their own group but it is closest to the properties of nonmetals

medals are on one side of the periodic table and nonmetals are on the whole other side. what side are medals and nonmetals on

nonmetals: right metals: left metalloids are in between them

is every mixture also a solution? is every solution also a mixture?

not every mixture is a solution but all solutions are mixtures

in which of the six branches of chemistry would a scientist be working if he or she were doing the following? the study of carbon compounds investigating energy relationships for various reactions comparing properties of alcohols with those of sugars studying reactions that occur during food digestion

organic physical organic biochemistry

O S Cu Ag

oxygen sulfur copper silver

each element has characteristic properties and have organized them on a chart in groups based on their properties. this is called the

periodic table

classify these as either physical or chemical changes? tearing a sheet of paper melting a piece of wax burning a log

physical physical chemical

is breaking an egg a physical or chemical change?

physical because the appearance is being altered not the substance

give an example of a physical and chemical change

physical change: cutting something chemical:molding bread

give an example of a physical change involving iron and a chemical change involving iron

physical change: the iron changes its shape (bends) chemical change: the iron rusts from the rain

difference between physical and chemical properties

physical changes the structure/appearance and chemical changes the substance

name six branches in the study of chemistry

physical chemistry, organic chemistry, inorganic chemistry, anlytical chemistry, biochemistry, theoretical chemistry

physical science is the study of what and why is it important in chemistry?

physical science is the study of nonliving objects and materials. chemistry is a study of physical science

what is the main difference between physical properties and chemical properties?

physical: the appearance changes but not the identity of the substance chemical: the substance itself changes

theoretical chemistry

predicting the properties of new materials

how are properties useful in classifying materials

properties can help reveal the property of the unknown substance

potassium+water---potassium+hydrogen

reactants: potassium/water products: potassium/hydrogen

chemical property

relates to a substances ability to undergo changes that transform it into a different substance

what is science and what does a scientist do?

science is the study of the natural world. we need to know why things happen. scientist study any branch of the natural world.

how do you decide if a sample of matter is a solid, liquid, or gas?

solid: definite volume/shape liquid:definite volume but changing shape gas: doesnt have a definite volume or shape

reactants

substances that react in a chemical change

families

the elements in a group are referred to as a ___

plasma

the fourth state of matter is found in fluorescent bulbs and stars. it has a high temperature and its matter is made up of charged particles. like a gas it takes up the place of its container, unlike a gas tho its particles can be influenced by electrical charges (ex: lightning bolt is made up of air particles that have been converted into plasma)

applied research

the goal of applied research is to solve problems. in chemistry it includes finding materials with certain properties. sometimes in chemistry is has the goal of learning how to prevent a certain reaction from occurring, or how to control the reaction

basic research

the goal of basic research is to increase knowledge. it is the study of the properties of a chemical and what happens when chemicals are mixed. done out of curiosity. new products/technology are created

technological development

the goal of tech development is to come up with new products and processes that improve the quality of life. new technologies come from basic and applied research/ wanting to make a new product

periods

the horizontal rows of elements in the periodic table are ____ (physical and chemical properties change in somewhat a regular patter as you move from left to right) (elements closer to each other in the same period are more similar than elements farther apart)

analytical chemistry

the identification of materials

the periodic table shows what

the name, the symbol, and its atomic number

compare the composition of sucrose purified from sugar cane and the composition of sucrose purified from sugar beets

the same composition is produced. sugar is sugar it doesnt matter where it is from

organic chemistry

the study of materials with carbon (once was or is living)

inorganic chemistry

the study of non organic chemicals

biochemistry

the study of the chemisty of living things

physical chemistry

the study of the properties of matter and its relationship to energy

products

the substances formed by the chemical change

changes of state

the three common states of matter are solids, liquids, and gasses. one type of physical change is a change from one state to another (change of state- the change of matter from one state to another) (when substances change states the movement/distance of the particles of matter changes but not the matter itself)

groups

the vertical columns of the periodic table (contains elements with similar chemical properties)

noble gasses

these are usually unreactive. since they are unreactive makes them very different from other families of elements. (group 18 is noble gasses)

suppose different parts of a sample material have different compositions. what can you conclude about the material

they are different elements

how is a liquid similar to a gas

they both don't have a definite shape

what is the significance of the horizontal rows of the periodic table

they show that elements close to each other are similar to each other

what is the significance of the vertical columns of the periodic table?

they show the groups

what type of substances do chemists work with?

they work with chemicals

write two questions that a chemist could try to answer about a material called "chemical x"

what is chemical x? how does it react with other chemicals?

what is meant by a change of state?

when a substance changes from a gas to a liquid to a solid or the other way around

why is basic research important to technological development?

you need to know the regular info to be able to use that info to create new products