Chapter 1

Chapter 1 foundations

• Taxol

  • substance created by Wani and Wall through the collection of various parts of trees and mixing them together

  • then ten years studying this new substance to understand its creation and process

  • Horwitz, a later scientist also studied this substances and learned that it can be used to prevent cancer cells from reproducing

    • this led to various other scientific investigation and it was entered into chemical trials and given the name Taxol or paclitaxel

  • harvesting the bark to create taxel killed its trees at a rapid pace which would ultimately lead the trees to be depleated

  • today pharamices use different medicines ot produce their own taxel

1.1 Chemistry in everything you do

• chemistry: understanding what substances are made of and how they behave

• chemistry = “the central science”

1.2 Describing Matter

• matter= anything that has mass and takes up volume

• chemistry: the study of matter and its changes

• Composition and structure

  • composition: the sijmpole componenets that make up the material

  • structure: both the composition and arrangement of those simpler substances

• Pure substances and Mixtures

  • atoms: the fundamental units of matter

    • represented by scietists as tiny sphers with one or two letter symbols

  • element: simplest form of matter

    • ex: gold, silver, iron, oxygen, and nitrogen

    • all composed of unique types of atoms

  • compounds: substances composed of more than one element formed with fixed ratios

  • molecules: formed by atoms formed from many groups of molecules

    • atoms bind tightly together and behave as a single unti

      • water molecule is two hydrogen and one oxygen

    • some elements exists as molecules

      • ex: hydrogen, nitrogen, and oxygen pair with themselves to form diatomic molecules

  • pure substances: materials that are only composed of one element or compound

  • mixtures: contian more than one substances

    • not always bound to a fixed ratio

      • ex: brass and bronze→ the ratios in which metals they are formed with are not fixed

    • homogeneous mixtures: components are evenly blended throughout

      • ex: coffee

    • heterogeneous mixtures: regions have significantly different composition

      • ex: chocolate chip cookie dough

  • key difference between compounds and mixtures

    • mixtures can be separated into their individual componenets without changing the identity

    • compounds cannot be separated without changing the substances into their elemental forms

• States of Matter

  • matter can exist in three forms: solid, liquid, gas

    • solid to liquid=melting

    • liquid to gas=vaporization

    • gas to liquid=condensation

    • liquid to solid= freezing

  • heating a substances leads the atoms to move quickly which allows the atoms to break from their solid state to a more liquid one, and eventually from a liquid state to a gas

    • the opposite effect when cooling

  • the behavior of any substance is determined by the arrangement of the particles that compose the substance

• Properties and Changes

  • physical properties: properties of a substance that can be measured without changing the idntity of the substance

    • ex: color, temperature, mass,m volume, shape, hardness, flexibility

    • physical changes can occur without altering the identity of the substance

  • chemical properties: cannot be measured without changing the identity of the substance

    • ex: flammability

    • when a substance changes into something different, it has gone through a chemical change

      • also known as chemical reaction

1.3 Energy and Change

• energy: the ability to do work

  • usually used to describe chemical and physical changes

  • two forms: kinetic and potential

    • kinetic: energy of motion

    • potential: energy that is stored

  • heat energy: a form of kinetic energy

    • involves the kinetic energy of the particles within the substance

• ohysical and chemical changes are essentially changes in energy

• energy can also take many forms

• substances are usually described as high-energy or stable

  • high energy substances can bring about a change

  • stable substances are much less likely to react

• systems move toward the lowest energy state possible

• exothermic change: one that releases heat energy

• endothermic change: requires energy to occur

• ex:

  • carbon + oxygen → cardon dioxide + heat

    • release of energy→ exothermic

1.4 The Scientific Method

• scientific method: the approach that scientist take to solving problems

  • cyclical process of making observatoins, formulating new ideas, and testing those ideas through experiments

• hypothesis: tentative explanation that has not been tested

• theory: idea that is supported by experimental evidence

  • sometimes used to mean a paradigm, a way of thinking about a particular topic

  • theory also means an idea that is unproven

• scientific law: describes observations that are true in widely avrying circumstances

  • does not explain why something happens, only states that it does happen

• reseach does not progress from theories to law they are very seperate ideas

End of Chapter

• chemistry is matter, matter is anything that has a mass and takes up volume

  • matter is composed of atoms

• elements: made from only one atom

• compounds: made from more than one type of atom in fixed rations

• compounds can form lead atoms to form molecules

• mixtures contain more than one element or compound, ratios can also vary

• matter is described by chemical and physical properities

• energy is either kinetic (moving) or potential (stored)

• spontaneous changes involve moving from high-energy to low energy states

• scientifici method: is the systematic approach scientist use to formulate and test new ideas

• a theory explains how or why something works

• a law explains what is happening