Chemistry and You

Paclitaxel

Natural Science

3 Branches• Biological Sciences- the science of living things

• Botany, Zoology, Ecology, etc.

• Physical Science- the science of matter & energy

• Physics- forces and energy

• Chemistry

• Earth Science (Geology)- the science of Earth

• Geology, Meteorology, etc.

What is Chemistry?

Chemistry- The study of all substances (matter) and the changes that they can undergo.• Medicine, fibers, dyes, food,

perfume, developing film, wine making, production of Gas (oil), cleaning products, etc.

• Can you think of some examples of when a chemistry is happening?

The Central Science

Chemistry is considered the central science because it overlaps so many other sciences.• Biology, Medicine, Physics, Astronomy, Geology,

etc. And jobs!

• Engineering, public service, hair dresser, dental assistant, Nurse, Candy maker, Steel worker, Firefighter, Forensic Scientist, Medical examiner, etc.

Matter

Matter is anything that HAS MASS and TAKES UP SPACE.

4 States- solid, liquid, gas and plasma

Composition of Matter

Matter is comprised of:• Atoms- the smallest unit of an element

• Elements- a substance that cannot be broken down into a smaller substance

• Elements are represented by a 1 or 2 letter symbol.

• EX: C is carbon, O is oxygen, Fe is iron, Al is aluminum and Na is sodium.

• There are more than 110 elements we know of and all have distinct properties and behaviors.

• Compounds- a substance made of 2 or more elements.• When 2 or more elements combine chemically they form

a compound. Every compound is unique and different from the elements it contains.

• Compounds have set ratios.

• EX: Sugar C6H12O6.

• EX: Water (H2O) will always have 2 H atoms to every 1 O atom.

Molecules: when elements combine to form compounds, the smallest unit that exhibits all the properties of the compound is a molecule.

Most molecules are made of atoms from different elements (H2O) but some are made of the same element.

• EX: Ne, O2, H2, Cl2, P4, S8.

• EX of compounds

Chemical Formulas

Chemical Formula: shows how many of each element are a molecule (the basic unit) of a compound. • The # is written as a subscript. NO subscript is used

to denote ONE. EX: Carbon dioxide is CO2 not C1O2.

When a # is placed in front of a chemical formula, it represents how many molecules present. • EX: 9 C6H12O6 means that you have 9 sugar

molecules.

REVIEW SECTION Kinetic Theory

• Describes the behavior of matter • All matter is made of atoms and molecules that act like tiny

particles.

• These tiny particles are always in motion. The higher the temperature, the faster the particles move.

• At the same temperature, the massive (heavier) particles move slower than the less massive (lighter) particles.

4 States of Matter

There are 4 states of matter the kinetic theory helps describe: solids, liquids, gases and plasma. • These states of matter are physically different.

Solid

Molecules do not move freely, they vibrate in place, giving solids a rigid structure.

They have ordered, fixed, and tightly packed arrangements due to chemical bonding and intramolecular interactions

LEAST AMOUNT OF ENERGY

Liquids

Molecules are closer together and moves faster than solids.

Molecules are weakly attracted to one another moving less freely than gas. They move randomly and fill the container in which they are held.

The rate at which a liquid moves/flows is known as its viscosity. The slower moving= more viscous. Ex: Glass.

Gases molecules are in constant, random

motion spreading out in all directions (diffusion).

They exert pressure. The pressure is made by individual gas molecules hitting the sides of the container.

As the temperature rises, the molecules begin to move faster = the pressure increases

(the molecules hit the sides more often and with greater energy/force= increased pressure).

Plasma

Usually an ionized gas.

Does not definite shape.

Conducts electricity well.

Effected by electric and magnetic fields.

MOST AMOUNT OF ENERGY

Changes in State Energy’s Role: required to move or change matter.

Energy is transferred in all changes of state. • ENERGY REQUIRED- to melt or evaporate any substance.

• Sublimation- physical change of a solid to gas- energy is required.

Energy Released- during condensation. Gas → Liquid or Liquid → solid.

Changes of state: • solid → liquid → gas, does not change the composition or the

mass.

Law of Conservation of Matter/Mass

Law of Conservation of Matter/Mass: Matter/mass cannot be created or destroyed. • It only changes form.

Properties of Matter Chemical Properties: how a substance reacts with

other substances, chemically, to form new substances. *** composition will be changed***• Ex: rust (the ability of iron to react with oxygen), and

combustion/flammability. Electronegativity, ionization potential, pH , heat of combustion, toxicity, stability, flammability…

Reactivity- the ability of a substance to react chemically with another substance. How much it will react depends on what they are reacting with and in what kind of environment the rxn is occurring.

Physical Properties: characteristics of the substance which can be measured/observed without changing the composition of the substance.• Melting point- temp. @ which a solid becomes a liquid.

• Boiling point- temp. @ which a liquid becomes a gas.

• Density- the mass per unit volume.

• Buoyancy- the force with which a more dense fluid pushes a less dense substance upward.

• * These properties help determine the use of the compound. *

Prop. Of Matter cont.

Chemical Changes: occurs when a substance changes composition to form a new substance.

• Na2O + H2O→ 2NaOH

Combustion:

CH4 + 2O2→ CO2 + 2H2O

Physical Changes: only the physical properties/form change. The substance may look different but the atoms of the substance are not changed.

• Ex: changes of state- solid to liquid to gas. The substance looks different but the composition remains the same (H2O is still H2O).

• Grinding peanuts to make peanut butter.

• Pounding a gold nugget to make a ring• ** The melting point, density or color of gold doesn’t change**

• Melting, freezing & evaporation = physical changes.

• So is dissolving…