The Pursuit of Knowledge

[Chemistry - Covalent Bonding]

2009-10-11T05:41:00.000-07:00

Simple molecular structure

In a simple molecular substance, the molecules in the substance are held together by weak intermolecular forces. Very little energy is required to overcome these weak intermolecular forces and separate the molecules from each other. Hence, simple molecular substances have low melting and boiling points. They are volatile.

Simple molecular compounds do not conduct electricity as they do not possess mobile ions or electrons within their structure.

Macromolecular structure

In the case of a diamond:

Diamond is hard as it has a rigid network of repeating units of tetrahedrally arranged carbon atoms joined by strong covalent bonds. These atoms do not move out of their position when force is applied due to these strong covalent bonds that exist among them.

Diamond has a high melting point as diamond has a macromolecular structure comprising of a network of repeating units of tetrahedrally arranged carbon atoms held together by strong covalent bonds. Since a lot of energy is required to overcome these strong covalent bonds and change diamond from the solid to liquid state, Diamond has a high melting point.

Diamond does not conduct electricity as all the valence electrons of the tetrahedrally arranged carbon atoms are used for bonding. Hence there are no mobile electrons that move through the structure, disallowing diamond to conduct electricity.

Uses of diamond: Gemstones in jewellery, tips of drills.

In the case of graphite:

Graphite is soft and slippery as the layers of hexagonally arranged carbon atoms are held by weak intermolecular forces, and these layers can slide over each other.

Graphite has a high melting point as the hexagonally arranged carbon atoms within each layer are held together by strong covalent bonds. A lot of energy is required to overcome these strong covalent bonds and to change graphite from the solid to the liquid state. Hence graphite has a high melting point.

Graphite can conduct electricity as each carbon atom has a delocalized mobile electron that is not used to form covalent bonds. These mobile electrons are able to move along the layers from one carbon atom to the other and hence graphite is a good conductor of electricity.

Uses of graphite: lubricate machine parts that contain rubber, pencil lead, brushes for electric motors.

Human Geography [Key points]

2009-09-22T06:35:00.001-07:00

Industry
Factors influencing location of industry
-Sit Sit Rover...

Weight-gaining industries
-located near markets
pg 25 Toyota cars(Kelang Valley, Msia) - companies located in SEAsia
Brazil

Weight-losing Industries
-located near raw materials
--------pg22 eg Saw mills are located near forests
-logs are bulky and difficult to transport
-Sawn timber only 40% of the wood in a log

Global Industrial Shift
PUSH FACTORS
-high labour costs in DCs
-older work force in DCs
-strong labour unions in DCs
-older factories and infrastructure
-expensive land
-planning controls by government - few or no tax incentives

PULL FACTORS
-cheap land in LDCS
-cheaper labour in LDCs - 12hr/day, US$120/month, 6days
-strike-free eg in Spore (but not in Korea)
-new facilities, well planned infrastructure eg Spore(wafer fabrication, clean water)
-Government assistance
.-----.incentives, tax free 5 yrs
.-----.planned industrial estates
.-----.Free Trade Zones eg Hong Kong
.-----.Special Economic Zone eg Shen Zhen
-Large, ready markets

Facilitating factors
SPACE-SHRINKING TECHNOLOGY
a)transport tech- large cargo ships, jet aircraft
-------- reduce relative time and distance taken to travel between countries
b)Containerisation - higher speed + efficiency of transporting goods

COMMUNICATION TECH
"transmission of information between individuals or groups through use of satellite tech and optical fibre systems"
-enables emails and video-conferencing between headquarters and branches all over world

TNCs(or MNCs) WITH CAPITAL OF TECH
-large capital and expertise to operate far-flung companies all over the world

Factors Promoting trend of transference or global industrial shift
M - MNCs
S - Space Shrinking Tech
G - Govt incentives/planning
C - competitive advantage(land, labour, markets and raw materials)

Impact of trend of transference
-Shift in manufaturing from DCs to LDCs and corresponding decrease in employment in manufacturing in DCs
-By 1990's high tech manufacturing has shifted to LDCs
-Increase in foreign direct investment in LDCs(selected LDCs eg China, Thailand, Msia)
-increase in exports of manufacturing products in LDCs
-Growth of NIEs
- +/- of MNCs

NIEs
Tier 1 - 60's to 80's - 4 Asian Tigers
Tier 2 - 80's - Mix Beans Make Indonesian Pineapple Tarts
Tier 3 - 90's(outsourcing) - India, China, Vietnam, Chile(or is it chili?)(ICVC)

3 Characteristics
-fast rate of growth in manufacturing
-rising share of world exports of manufacturing
-fast growth in real per capita income

Case Study of electronics industry of India eg Bangalore
-land
-skilled labour - 169 polytechnics
-govt support
-market
-transport
-raw materials(gold, copper)

Challenges facing electronic industry
T - technology lagging behind
R - raw materials - shortage of equipment
I - infrastructure
.------.power failure
.------.traffic congestion
C - Competition from China, Msia
Dear - depletion of resourced - eg deforestation, coal, copper
Police - pollution eg by e-waste

Sustainability of industrial Devt
M - managing depleting resources - regulate land use
A - appropriate use of tech - remote sensing - more efficient
R - recycling of e-waste(reuse copper, lead, gold) eg ASH recyclers

MNCs
Benefits - REDDSSSS
------------FDI

Disadvantages - pollution
--------------------mass unemployment
--------------------exploitation 40000 fingers broken...
-------------------- Sweat shops
--------------------small firms squeezed out
--------------------squatter development - RU migration
--------------------deforestaton

...................................................................................................

FOOD

Factors influencing food variation
Affordability
-purchasing power(1/5 richest countries owns 85% of world's income)
-1 in 3 children in Asia, L.America, Africa are malnourished

Stability
-political conflict(Iraq, Afghanistan...)
-poor planning
-production of non-staple food eg Biofuels( Palm oil in M'sia, Coffee in Indonesia)
-bird flu+diseases
-natural hazards eg floods, droughts, earthquakes -> poor harvests

Accessibility
- globalisation - fast food outlets growing rapidly - access to diff types of fast food eg sushi outlets, KFC
- trade - greater access to food but trade barriers can limit access to food
.----------eg 1991 Iraq war
--------------. Trade embargo by US
--------------. less access to fertilisers
-transport facilities
.------.refrigeration - rapid distribution of perishable food is possible
.------.Natural Barriers eg landlocked countries of Afghanistan
-------------> less access to food
.------.Presence of food outlets eg supermarkets in urban areas
-------------> few in rural areas

Effects of variations in food consumption
Starvation( <1000kcal/day average ="2586kcal/day)
-----------1 child dies every 5 sec
-----------organs damaged - death

Malnutrition - inbalanced nutrients
-----------------LDCs
---------------------.rickets(lack vit D and calcium)
---------------------.anaemia(lack iron)
-----------------DCs
---------------------.anorexia
---------------------.bulimia

Obesity - more nutrients than necessary
-----------------high blood pressure
-----------------heart disease

Solution to food problems(responses to variations in food consumption)
-International Organisation eg World Food Program(WFP)
-.Food for World project in Somalia - build irrigation channels
-.School feeding program in Cambodia
------ nutritious breakfast
------ but still large no. of people suffering

-Government response
-------Food subsidies
----------.eg free school lunches for low income families
----------.BUT over reliance mentality
----------.INSTEAD, poor can learn skills - long term solution
----------.BUT require $ and effortm not easily achieved in LDCs
----------.SOMETIMES, corrupt government divert funds to corrupt officials

-------Stockpiling
------------.LDCs can't buy extra food for stockpiling
------------.DCs can afford to stockpile/refrigerated warehouse
-----------------eg Spore(3 months rice supply
-----------------sometimes, DCs stockpiling increase food price

-------Green Revolution
------------.HYV seeds eg IR58 - double rice yields
------------------------------------- 100 days to mature
------------.Irrigation
---------------------double cropping
---------------------reliable water supply
---------------------marginal land can be made arable
---------------------reduces flood/poor harvests/droughts
------------.fertilisers
------------.pesticides
------------.machinery eg harvesters, tractors - speed up farm operation

-Blue revolution
---------.Steady fish supply

-Production of non-staple food by LDCs
---------.eg coffee growing in Indonesia and Vietnam

Factors influencing intensity of food production
PSLE Pity

P hysical - relief, climate, soil(recliso)
S ocial - Land tenant and land fragmentation
E conomic - Demand
--.eg for coffee will encourage more farmers to grow coffee at the.expense of rice
--.capital - $needed for fertilisers, pesticides, machinery
P olitical - government policies
--.eg Spore's devt of high-tech farming to increase production
--.eg FELDA scheme in M'sia for rice cultivation in Kedah Plain-a success

T echnological - Green revolution
---------------------.IR58
---------------------.irrigation
---------------------.chemicals
---------------------.machinery

------------------- Blue revolution
---------------------.10% growth of fish farms per year
---------------------.Stable supply
---------------------------increase fertility of fish
---------------------------resistance to disease
---------------------------BUT
---------------------------reduce biodiversity
---------------------------nutrient pollute seas
---------------------------catch small fish to feed salmon - wastage
---------------------.Supported by ADB(Asian Devt Bank)

Effects of Food intensification(+/-)
I rrigation - Salinisation, water logging(-)
C hemicals - eutrophication, pollution of rivers and ground water(-)
GM - increase income(+)
-------stay fresh(+)
-------pest resistant eg Bt Corn(+)
-------increase nutritional value - golden rice(+)
-------health concerns
--------------lectin in potatoes(-)
--------------allergic reactions(-)
--------------not well-labelled hence consumers can't make informed decisions(-)
-------loss of biodiversity
--------------------.pest resistant plants eg Bt toxin in corn
--------------------- affect monarch butterfly(larvae die at a higher rate)
-------loss of natural species
--------------------.pollen of pest-resistant carried by wind/insects
--------------------- gene pollution of natural plant species
--------------------- loss of biodiversity

Effectiveness of Food production
-reduces starvation / malnutrition
-but dominance by agribusiness
--.compete with LDCs eg poor farmers can't compete
--.overproduction by agribusiness may create over supply + cause prices to fall
------eg coffee prices fall
-export of food crops eg by Punjab to Europe
-----.for pet food
-----.locals can't buy food as it is expensive
-lack of health education
-----.many still eat unbalanced diet
-unscrupulous(?) greedy producers
-----.contamination of food -tainted milk from China which contains melamine
----------- kidney stones
----------- death of babies

Addressing Challenges
-WFProgram for malnourished children in Cambodia
-Improvement in tech
------.transport network - better distribution
------.better food storage - through irradiation and vacuum packaging
-labelling of GM foods for health reasons

....................................................................

DEVELOPMENT

How to alleviate uneven devt

International Scale
a) International organisation
-----World Bank
--------.loans at low interest for building irrigation projects
------------eg Tirtomoyo village in Indonesia
-----Asian Development Bank
--------.higher quality of life in Asia
------------eg Bangladesh - Jamuna Multi-purpose Bridge project
-------------------------------->connects agriculture to city and port

b)International Agreement
----UNMDG
-------.to half poverty by 2015 (poverty=< color="#ffffff">----------eg Vietnam poverty has decreased from 59% to 24%

----UNCLOS (UN convention of the law of the sea)
------.protect coastal fishermen in countried
---------eg Peru (326km around city)
------.protect against water pollution
---------BUT lanlocked country do not benefit
----------eg Bolivia

National Scale
a)Improve water Supply and Sanitation
-----eg Parivartan Slum Networking Programme in Alimendabad
-------.Death rates decrease from 6.9/1000 to 3.7/1000

b)Improve education
-----eg Thailand - Hill Tribe Education Project
--------->"Education for All" Volunteer
--------->better farming methods
-------however,isolated locations, difficult to reach all

c)Population control eg 1 child policy in China(1979 onwards)
-----However difficult to reach all
---------.rural areas continue to have more than 2
-----Bad effect
-------. encouraged female infanticide
---------- causing an ageing population as fewer young people replace pop

d)Job creation and assisstance
-----microfinance eg KALAHI plan in philippines
--------------.3 mil ppl benefitted
---------however, need to diversify products
------------.poor need market access to sell goods
------------.hard to reach remote villages
-----Grameer Bank - provide microfinances
--------.to farmers in Bangladesh at very low interest rates
--------.to small scale entrepreneurs eg tailors

Credits: 4/3'08, and Geog teacher of 4/3'08 - Mrs Lim

[Chemistry - Ionic Bonding]

2009-08-22T04:14:00.000-07:00

What are ionic compounds?
Ionic compounds are made up of oppositely-charged ions held in fixed positions in a giant lattice structure by strong electrostatic forces of attraction.

Why do Ionic compounds have high melting and boiling points?
Ionic compounds have high melting and boiling points (non-volatile), as the lattice of an ionic compound is held together by strong electrostatic forces of attraction between the oppositely-charged ions. A large amount of energy is required to overcome these forces, and to change an ionic compound from solid to liquid state.

Are Ionic compounds soluble? Why?
Ionic compounds are generally soluble in water, as water molecules can separate the positive ions from the negative ions within an ionic compound, causing them to dissolve.
However, ionic compounds are insoluble in organic compounds.

Electrical conductivity of ionic compounds in different states:
Ionic compounds do not conduct electricity in the solid state as the ions are kept immobile by the strong electrostatic forces of attraction between the oppositely-charged ion. Since there are no mobile charged particles, electrical conduction is not possible.

Ionic compounds conduct electricity when molten as sufficient energy is provided and taken in by the ions to overcome the strong electrostatic forces of attraction, causing the giant lattice structure to break apart. Thus, the ions are free to move and can conduct electricity.

Ionic compounds can conduct electricity when dissolved in water as water molecules can separate the positive ions from the negative ions, breaking the giant lattice structure apart. Thus, the ions are mobile and can conduct electricity.

2009-08-22T03:22:00.000-07:00

22 August 2009 1823 hours: The birth of this blog

The blog to record Alvin's journey in pursuing knowledge.