...: 2010

4/30/2010

HEBATKAH SEORANG MANUSIA YANG BERNAMA GURU???

Assalamualaikum

Di kala zaman yang serba mencabar ini, GURU dianggap kurang mulia berbanding GURU pada zaman bapa atau mungkin datuk kita yang dulu. Apakah istimewanya manusia yang bernama GURU pada zaman ini?? siapakah yang boleh menjawab persoalan ini? Jika ditanya pada orang yang berikut::

pelajar : kami benci guru, rotan kami...mak ayah kami tak pernah rotan

ibubapa: jangan rotan anak kami

masyarakat: kerja guru senang...pegi pagi..balik tengahhari. gaji boleh tahan. banyak cuti. tugas bercakap dan mengajar sahaja. tak perlu duduk di tngah panas. cukup bulan gaji masuk.

guru: ajar pelajar ...taknak belajar, rotan nanti mak bapak marah, tak rotan nanti taknak belajar, keputusan jatuh nanti kena jawab, jawab pelajar malas tak boleh....

itu persoalan yang sering timbul pada zaman ini. manakah kedudukan seorang GURU. Adakah zaman ini waktu kerja guru masih separuh hari?? masuk 7.30 pg balik 1.00 tgh. Adakah masih wujud guru yang mempunyai waktu kerja sebegini?? GURU mengajar 30 org pelajar dalam satu-satu masa supaya 30 org pelajar tersebut menjadi manusia berguna. Pernahkah perasaan GURU dipedulikan? sikap pelajar zaman sekarang yang agak kurang sopan dengan GURU...adakah itu dipedulikan? siapa yang peduli?

SALAHKAH SEORANG GURU JIKA MENDIDIK MURIDNYA UNTUK BERTANGGUNGJAWAB DENGAN DIRI SENDIRI?
SALAHKAH SEORANG GURU MENEGUR KESILAPAN PELAJARNYA?
SALAHKAH SEORANG GURU MEROTAN MURIDNYA SEMATA-MATA UNTUK MENDIDIK?
SALAHKAH SEORANG GURU MEMARAHI MURIDNYA KERANA BERSIKAP MALAS?

DAN

DI MANAKAH KEDUDUKAN SEORANG GURU DI HATI ANAK MURIDNYA .....APABILA...ADA GURU MENGALIRKAN AIR MATA DEMI MEMPERBETULKAN SIKAP ANAK MURIDNYA?

TEPUK DADA TANYA IMAN.....

Selanjutnya taip di sini untuk paparan penuh.

Baca Selanjutnya..

3/27/2010

TAHNIAH SPM 2009 KIMIA SMK BERA ~ PECAH REKOD DALAM SEJARAH

TAHNIAH PADA YANG BERJAYA. INILAH HASIL DARI KESABARAN ANDA.... JANGAN LUPA CURAHKAN ILMU PADA YANG MEMERLUKAN .....KEKALKAN SIKAP ANDA WALAU DI MANA ANDA BERADA. JANGAN MUDAH LUPA DIRI...IRINGKAN SETIAP LANGKAH KITA DENGAN RESTU ILLAHI...JAUHI KEMUNGKARAN DAN MAKSIAT. SESUNGGUHNYA DUA PERKARA ITU YANG SERING MENGGAGALKAN MANUSIA DALAM HIDUP.... APA SAHAJA YANG KITA LAKUKAN...INGATLAH PADA YANG 'SATU'. SESUNGGUHNYA HIDUP KITA AKAN DILINDUNGI OLEHNYA....AMIN.

Selanjutnya taip di sini untuk paparan penuh.

Baca Selanjutnya..

Subscribe to: Posts (Atom)

CHEMICAL BONDING

Sodium Chloride :

explain how this compound can be formed.

§ Electron arrangement of sodium atom is ...................

§ Sodium atom has …………. valence electron.

§ Sodium atom …………… one electron to form sodium ion, Na⁺ and achieve a stable …………… arrangement.

§ Electron arrangement of chlorine atom is ...................

§ Chlorine atom has …………. valence electron.

§ Chlorine atom …………… one electron to form chloride ion, Cl^- and achieve the stable …………electron arrangement.

§ The sodium ion, Na⁺ and chloride ion, Cl^- formed are attracted to one another with strong force to form a solid sodium chloride, NaCl compound. The attractive ………………..force between the ions is called an ionic bond or electrovalent bond.

preparation of soluble salts (not Na, K, NH4+ salt)~ [chapter 8 form 4]

soluble salt : Copper(II) sulphate, CuSO₄Name two chemical substances to prepare the salt :

Sulphuric acid
Copper (II) Carbonate

Chemical equation :

H₂SO₄ + CuCO₃ à CuSO₄ + CO₂ + H₂O

Description :

1. 50 cm³ of acid is measured using a measuring cylinder and poured into a beaker. The acid is heated slowly.

2 Using a spatula, metal / metal oxide / metal carbonate powder is added a little at a time while stirring the mixture with a glass rod.

3. The addition of the solid powder is stopped when some solids no longer
dissolve anymore. (the solid is excess and all the acid is completely
neutralised by the solid)

4. The mixture is filtered to remove the excess solid powder.

5. The filtrate is transferred to an evaporating dish.

6. The filtrate is heated until saturated. (The filtrate is evaporated to

about one-third (1/3) of the original volume).

7. The saturated solution is then allowed to cool to room temperature

and the salt crystals are formed.

sample of question [solving problem using chemical equation]

question:

2HNO_3(aq)+ CaCO_3(s) à Ca(NO₃)_{2 (aq)} + H₂O_(l) + CO_2(g)20 g of calcium carbonate is completely reacted with excess of dilute nitric acid to produce calcium nitrate solution, water and carbon dioxide gas.

Based on the chemical equation, find the volume of carbon dioxide gas released at room condition.

[Relative atomic mass: Ca,40; C,12; O,16; H,1; N,14 ; Molar volume: 24 dm³at room condition]

problem solving :

Number of moles of CaCO₃ = 20 ÷ 100

= 0.2 mole

Based on the equation,

1 mole of CaCO₃ produced 1 mole of CO₂

Therefore,

0.2 mole of CaCO₃ produced 0.2 mole of CO₂

So,

0.2 mole of CO₂ = 0.2 X 24 dm³

= 4.8 dm³

note : unit is very important in numerical answer, no unit.....no mark that will be given!

Chemistry form 5 [Rate of reaction]

sample question :

When a sodium thiosulphate solution is reacted with hydrochloric acid, the rate of the reaction can be measured by timing how long it takes for a sufficient amount of sulphur to form so that a dark cross drawn on a piece of card below the reaction flask can no longer be seen.

1) What is the rate of reaction if the time taken for the cross to disappear in 50 seconds?

Answer: Rate = 1/Time = 1/50s = 0.02/s

2) Write the chemical equation for the reaction above.

Answer: Na₂S₂O₃(aq) + 2HCl (aq) --> 2NaCl (aq) + S (s) + SO₂(g) + H₂O (l)

chemistry form 4 [atom]

The word 'atom' comes from a Greek word that means 'something that invisible'. However, atom can be split!

According to modern atomic theory, subatomic particles like protons and neutrons form the nucleus of an atom, while electrons whirl around the nucleus in different orbits with such a tremendous speed that they seem to form layers of shells around it.

Scientist And His Findings

John Dalton (1766 - 1844)
i) All elements are made up small indivisible particles called atoms.
ii) The atoms of an element are alike but differ from those of other elements.

J.J. Thompson (1856 - 1940)
Suggested the the atom is positively charged sphere with electrons embedded in it.

Ernest Rutherfold (1871 - 1937)
Discovered protons, and suggested thet protons are concentrated in the nucleus - the centre of an atom - which is surrounded by a cloud of electrons.

Niels Bohrs (1885 - 1962)
Proposed that electrons are arranged in orbits surrounding the nucleus.

James Chadwick (1891 - 1974)
Discovered neutrons, and proposed that the nucleus contains protons and neutrons, with electrons moving in orbit surrounding it.

chemistry form 4 [Isotopes identified]

Most atoms have several naturally occurring isotopes. An isotope is an atom that contains a different number of neutrons in its nucleus from that of other atoms of the same element.

This means that different isotopes of an element have different masses, since both protons and neutrons contribute about equally to the mass of an atom.

Radioisotopes such as phosphorus-32, carbon-14, sodium-24 and iodine-131 emit radiations. Thus, detectors like Geiger-Müller counter are used to trace the presence of radioactive radiations.

Radioisotopes are used in agricultural, medicinal, archaeological and industrial fields.

Some examples of the various uses of radioisotopes are shown as below, in sector;

NUCLEAR ENERGY

Isotope Uranium-235 used to produce nuclear energy.

AGRICULTURE

Isotope Phosphorus-32 or Nitrogen-15 used to traces the rate of nutrient absorptions in plants.
Gamma Rays used to sterilises pests. Inhibits the sprouting of potatoes, onions and gingers.

INDUSTRY

Gamma Rays used to checks wear and tear in engines. Gauges or controls the content level in canned food.
Strontium-90 used to gauges or controls the thickness of paper and metal in industries.
Cobalt-60 used to detects crack in metal or concrete structures.

Chemistry form 4 [Kinetic Theory of Matter]

Matter is made up of small and discrete particles, which are constantly in motion and contain kinetic energy.
Solid particles are held by strong forces of attraction, which packed them closely in an orderly manner. Thus, solid has a fixed volume and shape. Solid particles have limited motion; they can only rotate and move about a fixed position.
Forces of attraction between liquid particles are weaker than those in solid particles. Thus, the particles are arranged less compact and less orderly. Liquids have a fixed volume but not a fixed shape. The particles can vibrate, rotate and move throughout the liquids.
Particles in gas are held by very weak forces of attraction. The particles are very far apart from each other and are in constant motion. The particles vibrate, rotate and move randomly. Gas does not have a fixed shape or volume and can be compressed easily.

Chemistry form 4 [Periodic table and elements]

1. Lothar Meyer (1830-1895)
This German chemist recognised periodic behaviour based on his graphs of the atomic volume of elements against their atomic weight.

2. Dmitri Mendelev (1834-1907)
This Russian chemist made a table of elements and left a gap for elements that had not yet been discovered.

3. Antoine Lavoisier (1743-1794)
This French chemist classified elements into four groups - gases, non-metals, metals and earths.

4. John Newlands (1837-1898)
This English chemist's law of octaves stated that when elements were placed in the increasing order of atomic weight, the properties of elements fell into a pattern at regular intervals.

5. Henry J. G. Moseley (1887-1915)
This British chemist rearranged the elements in order of increasing atomic number.

6. Johann Dobereiner (1780-1849)
This German chemist proposed the law of triads, which stated that elements came in groups of three.

Copyright © 2009 by ...

Template by Blog Templste 4 U | Blogspot Tutorial