Friday, September 18, 2009

Selamat Hari Raya Aidilfitri




~ Cikgu Naza ~

Tuesday, September 08, 2009

2 Sit UPSR Exam In Hospitals

NST

KUALA LUMPUR: Two students who are down with influenza A (H1N1) symptoms are among the 517,908 candidates nationwide who are sitting the Ujian Pencapaian Sekolah Rendah (UPSR) examination which begins today.

Education director-general Tan Sri Alimuddin Mohd Dom said preparations had been made for the students, one in Johor and the other in Penang, to sit the examination in hospitals.

He said these were among the measures taken to curb the spread of influenza A (H1N1) among UPSR candidates who were sitting the examination at 8,289 centres nationwide.

The Education Ministry had allocated about RM5 million for masks, hand sanitisers and thermometers for UPSR candidates, he said here yesterday.

He said an isolation room was available at all examination centres to accommodate those with a body temperature of above 37.5oC during screenings, which would be conducted upon their arrival at the centres. - Bernama

[Chemistry Form 4] Alkaline Aqueous

Hydroxides of sodium, potassium, magnesium and calcium are bases. Bases have many common features: they have a bitter taste, are slippery to the touch, change the colour of indicators, etc. Aqueous solutions of soluble bases are called alkalis.

Solution vs Ionisation
Some strong bases like calcium hydroxide aren't very soluble in water. That doesn't matter as what does dissolve is 100% ionised into calcium ions and hydroxide ions. Thus, calcium hydroxide still counts as a strong base because of that 100% ionisation.

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Hydroxide that are alkalis:
  • NaOH
  • Mg(OH)2
  • KOH
  • LiOH
  • NH4OH

The following the dissociation of acids and base.

Hydrochloric acid
Formula: HCl
Equation to show dissociation: HCL -> H+ + Cl-

Nitric acid
Formula: HNO3
Equation to show dissociation: HNO3 -> H+ + NO3-

Ethanoic acid
Formula: CH3COOH
Equation to show dissociation: CH3COOH -> CH3COO- + H+

Potassium hydroxide
Formula: KOH
Equation to show dissociation: KOH -> K+ + OH-

Sodium hydroxide
Formula: NaOH
Equation to show dissociation: NaOH -> Na+ + OH-

Calcium hydroxide
Formula: Ca(OH)2
Equation to show dissociation: Ca(OH)2 -> Ca2+ + 2OH-

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