Revision acid base with answers

Revision acid and base

1) Give formulae for these substances

A) hydrochloric acid HClB) sulphuric acid H2SO4

HNO3

CH3COOHC) nitric acid

D) ethanoic acid

E) Sodium hydroxide NaOH

F) Potassium hydroxide KOH

G) Barium hydroxide Ba(OH)2

2) Give examples of

• A) strong acidsHCl, H2SO4, HNO3

• B) Weak acids CH3COOH, ethanoic acid

• C) Strong alkali NaOH, KOH, Ba(OH)2

• C) Weak alkali NH4OH,

3) State 4 chemical properties of acids

• A) reacts with metals to form

• B) reacts with oxide metals to form

• C) reacts with alkali to form

• D) reacts with carbonate metals to form

SALT + HYDROGEN GAS

SALT + WATER

SALT + WATER

SALT + CARBON DIOXIDE + WATER

Beaker A Beaker B

a) Add blue dry litmus paper

b) Add magnesium ribbon

c) Add marble chips

Fill in the table below

BLUE LITMUS PAPER CHANGE TO RED

EFFERVESCENCE OCCUR. COLOURLESS GAS RELEASE WHICH GIVES ‘POP’ SOUND WHEN TESTED WITH BURNING WOODEN SPLINTER

EFFERVESCENCE OCCUR. COLOURLESS GAS RELEASE WHICH TURN LIME WATER CLOUDY

NO CHANGE

NO CHANGE

NO CHANGE

• Which beaker shows acidic property? Why?

Beaker A because hydrogen chloride ionised in water to form H+ ions. Therefore it shows the acidic properties

• What is the role of water in this experiment?

To ionise hydrogen chloride into H+ ions and show its acidic properties

Write chemical equations for reactions in beaker A)

• i) with magnesium ribbon

• ii) with marble chips

222 HMgClMgHCl

OHCOCaClCaCOHCl 22232

Does solution formed in beaker A conduct electricity? Explain your answer

Yes because solution A contain mobile/free moving ion.

5) Table below shows some solutions with different pH

substance

Solution A

Solution B

Solution C

Solution D

Solution E

pH values

2 5 7 8 13

Which solution isa)A strong acid? b)A strong alkali?c)Neutral solution?d)Weak acid?e)Weak alkali?f)Has high concentration of hydrogen ions?g)Has low concentration of hydroxide ions?

Solution ASolution E

Solution C

Solution BSolution D

Solution A

Solution E

6) Calculations on concentrations• 4 grams of sodium hydroxide is dissolved in

100 cm3 of water• Calculate concentration of the solution

formed in: A) g/dm3A) g/dm3

6) Calculate concentration of the solution formed in

B) mol/dm31000 cm3 = 1 dm3

8) Calculations on formula, mole = MV/1000 and

mole = mass/molar mass• How many moles of NaOH contained in 100 cm3

of 2.0 mol dm-3 NaOH solution ?

What is the mass of NaOH needed to make a solution of 100 cm3 NaOH concentration 0.2 moldm-3? ( given RAM Na, 23: O,16: H,1)

What is the concentration of 0.5 moles HCl in a volume of 100 cm3 solution ?

7) Calculations on titration• 100 cm3 of 0.2 mol /dm3 sulphuric acid

neutralise exactly 100 cm3 of sodium hydroxide solution

Calculate the concentration of the sodium hydroxide solution

[H+] Ma Va = [OH] Mb Vb2x 0.2 x 100 = 1 x Mb x 100So Mb = 2 x 0.2 x 100 /100 = 0.4 mol dm-3

8) Calculations on dilution

• 90 cm3 of distilled water is added to a volume of 10 cm3 of nitric acid with a concentration of 2.0 mol /dm3. What is the concentration of acid after the dilution?

32

2

2211

2.0

)100()10(2

moldmM

M

VMVM