Acids and Basessss

Question 1

Define Acid, Alkali and Base!

Answer 1

1. Ac = a species that releases H+ ions in aqueous solutions
2. Al = A BASE that dissolves in water, relasing OH- ions into water
3. Ba = Species that NEUTRALISES an acid, able to ACCEPT H+ ion, producing salt…

Question 2

Difference with strong/conc acid…..

Answer 2

• STRONG = Acid that COMPLETELY DISSOCIATES in solution, releasing all H+ ions, fully ionising
• CONC = greater number of moles of acidic molecules per unit volume…..

Question 3

explain a weak acid….

Answer 3

• PARTIALLY ionise and dissociate H+ ions
• Reversible reaction, due to constant association+dissocaiation at any 1 instant…

Question 4

Ionic equation rules….

Answer 4

1. NO CANCELLING of COVALENT MOLECULES! (e.g. water…)
2. Cancell all spectator ions….

Question 5

4 common neutralisation reactions…

Answer 5

1. Metal oxide+Acid» SALT + WATER
2. Metal Hydroxide+Acid» SALT + WATER
3. Metal Cabonate+Acid»SALT + WATER + CO2
4. Alkali+Acid»SALT + WATER

Question 6

Acidic ionisation with MULTPLE hydrogens….?

Answer 6

1. Dissociated first H+, behaves as STRONG ACID(complete..)
2. All FOLLOWING H+ dissociates, as a WEAKER ACID (partiall/reversible), with charge on anion becoming more -ve…!!!

Question 7

Why is ammonia consdidered a base?

Answer 7

1. Has 1 lone pair on central atom
2. As a BASE, it can accept any H+ ion (proton ACCEPTOR!)
3. Hence, H+ ions can be accepted, via DATIVE covalent bonds&raquo_space;> forms NH4+ as a base!!!!

Question 8

How to prepare a STANDARD solution…?

Answer 8

1. Accuratly measure a SOLID MASS via top-pan balance
2. Dissolve solid in d-water, and transver to volumetric flask…
3. Fill V-flask to graduation line (BELOW meniscus)
4. Slowlyyyyy invert to mix solution..!

Question 9

Purposes of a Titration..?

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Answer 9

1. Concentration of solutions
2. Identifying unkown solutions
3. Finding substance purities

Question 10

Titration calculations?

Answer 10

1. FIND THE MOLESSSS
2. Use stochiometry
3. Balance, dont forget 10* scaling when needed…

Question 11

CONVERSION of gmol-1 to moldm-3??

Answer 11

1. DIVIDING THE FINAL MASS BY THE Mr OF SUBSTANCE!