Science, chemistry and measurement Organic, and Biological Chemistry: Structures of Life. 3rd...

© Endeavour College of Natural Health endeavour.edu.au

Chemistry Enabling Course

Module 1

Science, chemistry

and measurement


Module 1

o 1 General introduction

o 2 What is science?

o 3 Introduction to chemistry

o 4 Measurement and its units


1 General introduction

o 1.1 Welcome

o 1.2 Module aims

o 1.3 How to use these Modules

o 1.4 How to study chemistry


1.1 Welcome

o Welcome to the chemistry enabling module at the Endeavour

College of Natural Health.

o Today the complementary medicine practitioner is expected to have

a working knowledge of human physiology, biochemistry, disease

processes and pharmacology.

o These areas are all underpinned by an understanding of chemical

principles.

o People use chemistry everyday - in medicine, cookery, brewing and

wine making, growing crops and animals, architecture and building,

and forensic science.

o Chemistry has helped solve our practical problems and satisfy our

curiosity about what the world is made of.


1.2 Module aims

o These Modules are designed to provide a smooth

transition into the Endeavour introductory chemistry

courses.

o It might have been some time since you last studied

chemistry or perhaps you have not studied any yet.

o People are often concerned about how hard they think it

is going to be – particularly if they have little science

background.

o We think that "with patience and time, anybody can learn

chemistry" (Guch 2003, p. 9).


1.3 How to use these modules

o This Enabling chemistry course is divided into four modules, which generally follow the material provided in lectures.

o We suggest that you start at Module 1 and work through each one in order.

o It is important that you complete each exercise, as you will be learning how to write in chemical language and understand chemical terminology along the way.

o Each module has core information, exercises, web links, suggested glossary terms and references. The references are included so that you know where the information comes from; except for your text book, you will not be required to look up the references, but you might want to read more about some points for your general interest.


1.4 How to study chemistry

o To make the task of learning chemistry easier, follow

these steps:

• Learn the vocabulary

• Practice the processes

• Slow and steady gets there in the end

• Equip yourself with number skills

• Look at the big picture and keep the goal in sight

What you will need to complete this course:

• Student number, Internet access, enrolment in an introductory

chemistry course, the textbook, a notebook, writing materials


2 What is science?

o 2.1 What is science?

o 2.2 The scientific method

o 2.3 Models and the scientific method


2.1 What is science?

o The word "science" comes from the Latin word scientia,

meaning knowledge of the world around you (Lofts and

Evergreen 2000, p. 2).

o Science is also a way of asking and answering questions

about the physical universe. In science, these questions

need to be put in a way that can be tested and

measured.

o Scientists try to identify and describe what happens and

then try to explain why or how things happen.

o Once scientists have discovered some order, they then

use it to predict what might happen next.

o


2.2 The scientific method

o The scientific method – a way of asking questions,

developing ideas and testing them

o It describes a process of working scientifically. It is

common to all the sciences and can be divided into

steps:

• making observations

• looking for a hypothesis

• experimenting

• evaluating the hypothesis

o A new theory?


2.2 The scientific method

o The scientific method represents a logical approach to

explaining an observation.

o All discoveries are subject to the scientific process.

o Discoveries lead to new theories and directions.

New directions

Source:

http://www2.nau.edu/~gaud/bio

372/class/behavior/sciproc.htm

http://www2.nau.edu/~gaud/bio372/class/behavior/sciproc.htm


2.3 Models and the scientific method

o The real world is more complex than the limits set up in

your experiment

o we are always working with some kind of model of

reality

o Improvements in understanding lead to more realistic or

life-like models


Activities

o Start your own Glossary of terms by drawing up a table with two columns, one for the term and the second for the explanation or definition. Look for the bolded terms in the text above (for example, science and the scientific method). Write down the definitions of science and the scientific method. You can use your textbook to help you.

Term Definition/explanation

Science

Scientific method

o RQ1: Explain in your own words how a theory is developed in science. Explain how the scientific method differs from “traditional” knowledge. Suggested answers to the Review questions (RQ) can be found in Appendix A.


Module 1 References

o Textbook

o Timberlake, Karen C. 2010. General, Organic, and Biological Chemistry: Structures of Life. 3rd edition. Pearson Prentice Hall, Upper Saddle River, NJ, USA.

o

o Bibliography

o Atkin J, Barnard I, Robards K et al. 2009. Introduction to Chemistry SSS010 Study Notes 2. Division of Student Services 201045. Charles Sturt University, Albury New South Wales.

o Ball P 2002. The Ingredients: A Guided Tour of the Elements. Oxford University Press: Oxford

o Guch I 2003. The Complete Idiot’s Guide to Chemistry. Alpha Books/Penguin: New York, NY.

o Moore, J T 2003. Chemistry for Dummies. Wiley Publishing: New York, NY.

o Newmark, A. 1993. Chemistry. Dorling Kindersley Eyewitness Guides (in association with the Science Museum). London:

o Royal Society of Chemistry, Chemsoc, Burlington House, Piccadilly, London, W1J 0BA, UK. Chem Soc Timeline. Dalton – Atomic Theory 1803 http://www.rsc.org/chemsoc/timeline//pages/1803.html)

o Senese, F 2005. General Chemistry Online! Companion Notes Dalton's atomic theory. http://antoine.frostburg.edu/chem/senese/101/atoms/dalton.shtml

o Watzman, H. 2009. Earliest evidence for pottery making found. Nature News. Published online 1 June 2009 | Nature | doi:10.1038/news. 534.

http://antoine.frostburg.edu/chem/senese/101/index.shtml


3 Introduction to chemistry

o 3.1 Chemistry in the ancient world

o 3.2 Alchemy to modern chemistry

o 3.3 Modern chemistry

o 3.4 Classification of matter

o 3.5 Physical and chemical change

o 3.6 Gases and the particle theory

o 3.7 Introduction to the gas laws


3.1 Chemistry in the ancient world

o Since humans learnt to control fire, we have used chemistry in processes such as cooking food and baking clay - possibly the earliest found remains of fired pottery are about 18,000 years old (Watzman 2009)

o Other processes included smelting ore, fermenting wine, smoking and salting food, making glass (about 3000 years old), and lacquer, paper and gunpowder production

o In Ancient Greece, ideas about “atomos” were discussed

o Aristotle (384 BC–322 BCE) helped develop Plato’s four-element theory (earth, air, fire and water), which shaped western ideas on matter for 1500 years


3.2 Alchemy to modern chemistry

o The word “alchemy” comes from the Arabic al kimia. The alchemists burnt, distilled, melted and condensed many substances

o Distillation, used to prepare essential oils for medicine, developed from alchemy, and new elements and substances were discovered

o In the 1600s, some alchemists such as Robert Boyle became “chymists” – they demanded that Aristotle’s ideas were tested by experimentation – this lead to rapid progress

o In 1803, John Dalton - the “father” of modern chemistry –described a recognizably modern atomic theory


3.3 Modern chemistry

o Chemistry is now a major branch of modern science.

o Chemistry deals with the study of "substances",

o Chemistry is important because most of the other sciences use it as

a tool for solving problems (Guch 2003, p. 9).

o Some definitions of chemistry include: "the study of the composition,

structure, properties, and reactions of matter" (Timberlake 2010, p.

2); and "using our knowledge of how matter is put together and how

it interacts with other matter to solve confusing problems" (Guch

2003, p. 4).

o chemistry is "the study of matter".

o Matter is “anything that has mass and takes up space” (Timberlake

2010, p. I-15).


3.4 Classification of matter

o Matter can be classified by its:

• Uniformity, reactivity, physical state and its

composition

o Matter:

• is the material that makes up a substance.

• is anything that has a mass and occupies space.

• makes up the things we see everyday, such as water, wood,

cooking pan, clothes, and shoes.



Uniformity• Homogeneous - uniform throughout

– e.g. lump of salt

• Heterogeneous - not uniform

– e.g fog has two phases (air and water)



Reactivity

o Different types of matter will react differently.

o e.g: metals (such as copper) will react with acids to form

hydrogen gas and a salt (a metal combined with a non-

metal) but non-metals will not.

o Acids and bases will also react with different substances,

and can neutralize each other.



Physical states of matter

o The three physical states of matter are solid, liquid and

gas.

o Most matter can exist in all three states.

• E.g: ice is water in the solid state, water is the liquid state, and

steam is water in the gaseous state.

• Steam and ice have different properties because they are two

states of water.

o The three states are described by the particle theory

o Matter can change states



The particle theory

o compares the different states of matter by the shape and

volume of matter, arrangement, movement and

interaction between the particles.

o is useful for explaining some aspects of how matter

behaves, such as changing state

o The following slide provides more detail


3.4 Classification of mattero Solid

• has definite shape, has definite volume and is very

hard to compress.

• particles vibrate in fixed positions, have strong

attractive forces between them and are packed

closely.

o Liquid

• takes on the shape of the container, flows and is

virtually incompressible.

• particles move freely, have attractive forces between

them and are fairly closely packed.

o Gas

• has an indefinite shape and volume.

• Takes the same shape and volume as the container.

• Particles have little or no attractive forces between

them

• Particles are far apart and move fast.



25

Changing states

o Melting - a solid to a liquid.

o Freezing - a liquid to a solid.

The freezing (melting) point of

water is 0oC.

o Evaporation - a liquid to a gas

(it occurs at the boiling point).

o Condensation - a gas to a

liquid (at the melting point).

o Sublimation – a solid changes

directly to a gas.

o Deposition - a gas changes

directly to a solid.



Composition

o Matter can be classified according to its complexity

(pure substances or mixtures)

o A “substance” is matter of definite composition and

properties

A pure substance:

o Is made of one type of substance

o Has a specific composition.

o Is an element when composed of one type of atom.

o Is a compound when composed of two or more

elements combined in a definite ratio.



A mixture:

o Two or more substances that are physically mixed, not chemically

combined (homogenous or heterogenous).

o Substances that can be separated by physical methods

o Two or more substances in different proportions.

o Homogeneous mixture

• The composition is uniform throughout.

• The different parts of the mixture are not visible.

o Heterogeneous mixture

• The composition is not uniform, it varies from one part of the

mixture to another.

• The different parts of the mixture are visible.


Activities

o RQ2: List some ways of classifying matter, such as those

described above, and briefly describe each.


3.5 Physical and chemical change

Physical properties and changes

o Physical properties can be observed or measured

without affecting the identity of a substance.

• e.g. melting point and density, colour, shape and lustre (how

shiny it is).

o Physical change is the change in physical properties

• e.g. water boiling or freezing, cutting up pieces of paper and

dissolving salt in water.


3.5 Physical and chemical change

Chemical properties and changes

o The chemical properties of a substance is the ability of

a substance to change into a new substance.

o In a chemical change, new substances are made.

o These changes are not easily reversed.

• e.g. burning wood, forming rust, and cooking an egg.


Activities

o RQ3: Describe in chemical terms the difference between

burning paper and cutting it up.


3.6 Gases and the particle theory

o Gases are made up of particles spread very far apart,

move rapidly and do not have a fixed shape or volume.

o Particles of one gas mix freely with those of another gas,

and gas particles can be easily squashed together or

compressed.

o The behaviour of an ideal gas follows the kinetic

molecular theory of gases.

• gas particles: move in straight lines, are not attracted or repulsed

by each other, are very far apart, have small volumes compared

to the volume of the gas, and have kinetic energy that increases

with temperature.


3.7 Introduction to the gas laws

Properties of gas: Pressureo Defined as the amount of force exerted by the particles in a gas as they hit

the sides of the container.

• If the container’s volume is reduced, then the particles will hit the sides more

often, increasing the pressure.

• If the temperature is increased, the particles will hit the sides of the container

with more kinetic energy and also more frequently, also increasing the pressure.

o A gas will move from an area of high pressure to low pressure.

o Units: the official SI unit of pressure is the Pascal (Pa)

o Other units of pressure::

• atmospheres (atm) and millimetres of mercury (mm Hg) or torr

• bars, used mainly by meteorologists

• pounds per square inch (psi).

o Other properties needed to describe a gas are its temperature,

amount of substance, and volume.



Boyle’s Law

o when the pressure of a gas is increased, then the

pressure is decreased proportionally (if the temperature

and amount of gas are constant) – if volume is doubled,

then pressure is halved.

o is useful in explaining why air flows into our lungs when

we inhale, and why air is “pushed out” when we exhale.

• When we inhale, the volume of the lungs increases, pressure

decreases and air flows in.

• The opposite occurs when we exhale.



Dalton’s Law of Partial Pressure

o The total pressure exerted by a mixture of gases under constant

temperature and volume was the same as adding up the pressures

exerted by each gas on its own.

o If oxygen has a pressure of 3 atmospheres, nitrogen 6 atmospheres,

and methane 1 atmosphere, the total pressure of the gases in the

mixture will be 10 atmospheres.

o Each gas also acts independently of the other.

o Dalton’s Law is useful in explaining the diffusion of gases across

membranes.

• e.g. in the lungs, at the same time oxygen diffuses into the blood to top-

up the oxygen concentration, and carbon dioxide, a waste product, is

released into the lungs to be exhaled



Ideal Gas Law

o combines several gas laws.

o It includes the gas volume, pressure, temperature and

amount of substance (or number of moles).

o It also contains R, the gas constant that changes in

number according to whether pressure is measured in

atmospheres or millimeters of mercury.

o The Ideal Gas Law can be used to calculate changes to

volume, pressure, temperature or amount of substance if

several conditions are changed at the same time.


Activities

• RQ4: List the types of measurements needed when working with

gases. Why is it relatively easy to work with gases rather than

solids or liquids?

• RQ5: Define pressure and list the units used to measure

pressure.

• RQ6: Name the gas law that applies in each of the following

situations: (a) measuring blood oxygen concentration after

surgery; (b) measuring lung capacity via the volume of exhaled

gas; (c) a change in air pressure after changes in gas

temperature and volume.


Module 1 References

o Textbook


o

o Bibliography











4 Measurement and its units

o 4.1 SI units

o 4.2 Larger and smaller measurements

o 4.3 Unit conversion

o 4.4 Exponents

o 4.5 Scientific notation


4 Measurement and its units

Measurements and units

o Science involves taking measurements – both

qualitative (exactly what, how and why changes occur)

and quantitative (how much is involved in those

changes).

o All measurements have two components to them: (i)

magnitude or value; and (ii) the unit.

• For example, if you want to know how much a patient weighs to

work out how much herbal extract to prepare, you need to know

both the number and the unit it is measured in. If you say the

number 75, then you need to know whether that is pounds or

kilograms!


4.1 SI units

o An international system of units was devised, the

SI System of Units

o From the French “Systeme International

d’Unites”, so that there was a uniform language

for measurements.

o The SI system, based on the metric system, is

used by scientists in their everyday work and is

the accepted system in international science

journals.


Activities

• RQ7: Write out the SI base units for length, mass, time, and

temperature together with their symbols. Refer to your textbook,

or if available, “Units and measurement” in the introductory

Mathematics module

• RQ8: Write out the SI units for area and volume.


4.2 Larger and smaller measurements

o You will be mixing solutions, weighing amounts and

making formulations in less than cubic metre and

kilogram quantities.

o The way we describe smaller or larger amounts in the SI

System is by the use of letters before the unit, called

prefixes


4.3 Unit conversion

o Sometimes in chemistry we use a mixture of units for different

purposes, such as temperature measured in Celsius degrees, and

Kelvin units.

o To get from one unit to another related unit is called "unit

conversion".

o To complete unit conversions you need to know how many of one

unit ‘make up’ the other unit. For example, 1 hour is made up of 60

minutes.

o This is known as a conversion factor.

o To make meaningful comparisons between units, they need to be

converted into the same units.

o As a healthcare professional you will be frequently asked to

complete unit conversions.


4.3 Unit conversion

Steps in the conversion of units

o Identify the given units and the required units:

• e.g. 0.5 mg/L is given and the required concentration is in %(w/v)

o Write a statement of the given units and what the units must

become:

• e.g. 0.5 mg in 1 L = 0.0005 g in 1000 mL (because there are

1000 mg in 1 g, and 1000 mL in 1 L)

o Change the new volume and mass by multiplying or dividing by the

same factor:

• e.g. since %(w/v) is in g per 100 mL, divide both by 10.

• 0.00005 in each 100 mL = 0.00005 %(w/v).

o There are different systems for converting one unit to another. Refer

to Timberlake 2010, Section 1.7 Problem solving).


Activities

• RQ9: Make a Table of commonly used prefixes in the SI system.

Refer to Table 1.6 of your textbook, or if available, “Units and

measurement” in the introductory Mathematics module

• RQ10: Convert 10 inches to centimeters, given that 1 in = 2.54

cm.

• RQ11: Convert 64 kPa to atmospheres (atm, units of pressure),

given that 1 atm = 101.3 kPa.


4.4 Exponents

o Exponents are also called powers or indices. It is often

convenient to write a number as a base raised to a

power. The number that has been raised is called the

power, or the exponent.

• For example, the number: 4 = 2 × 2, can be written as 22

• 8 = 2 × 2 × 2, which can be written as 23

o When a number is raised to the power of 2, it has been

squared.

o When a number is raised to the power of 3, it has been

cubed


Activities

• RQ12: Write out the following numbers in full:

• 102 =

• 105 =

• 2.56 × 104 =


4.5 Scientific notation

o There are very large and very small measurements in

science. For example, the width of a human hair is

0.000 008 m, which is written in scientific notation as

8 × 10-6.

o It is a simple process to write numbers in scientific notation:

o Rewrite the number with only 1 digit to the left of the decimal

point, then multiply by the appropriate power of 10.

o Scientific notation also makes it easier to gauge the size of a

number.

• e.g. the number 12010 in scientific notation

becomes 1.2010 × 104 and

0.000256 becomes 2.56 × 10-4.


Activities

• RQ13: Convert the following numbers to scientific notation:

2400 s, 86 m, 68 kg, 12,800,000 m

• RQ14: When the three is raised to a power of four, how many

times is it multiplied by itself?

• RQ15: How would the number in the previous question be

written as a number?

• RQ16: List the benefits of using scientific notation.

• RQ17: What number is 3 × 103.

• RQ18: What number is 2 × 104

• RQ19: In scientific notation, what is the answer to 3 × 103

multiplied by 2 × 104


Module 1 References

o Textbook


o

o Bibliography










Science, chemistry and measurement Organic, and Biological Chemistry: Structures of Life. 3rd...

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