Acids and alkalis

StarterWrite down any three facts you recall to do

with acids or alkalis.Any names?Any uses?

How do we detect them?

Acids and alkalis

StarterUnscramble the words to reveal some acids and

alkalis:dica cirtinumiods yhorxddieyhrolcdhciro cida

Acids and alkalis

StarterUnscramble the words to reveal some acids and

alkalis:dica cirtin nitric acidumiods yhorxddie sodium hydroxideyhrolcdhciro cida hydrochloric acid

Key facts you may know Acids:

from the latin “acidus” (sour), pH1-6 and found in our stomachs, vinegar and some batteries.

Alkalis:

from arabic “al qalīy” (plant ash), pH 8-14, found in detergents, added to soil to help some crops grow and to make soap.

Atomic facts to record Acids:

ALL contain “H” - hydrogen.

HCl is hydrochloric acid

HNO3 is nitric acid

H2SO4 is sulfuric acid

Alkalis:

Often contain a metal and “OH” - hydroxide

NaOH is sodium hydroxide

LiOH is lithium hyrdoxide

Atomic facts to record When they react in the correct proportions, they

cancel each other out – neutralisation:

sodium hydroxide + nitric acid → sodium nitrate + water

(pH 12) (pH 2) (pH depends (pH 7)

on the salt)

1) Use a measuring cylinder and measure 10 cm3 hydrochloric acid into a beaker.

2) Use a measuring cylinder and measure 10 cm3 sodium hydroxide and add about 9 cm3 to your beaker and stir it using the glass rod.

3) Add sodium hydroxide a few drops at a time. Test a drop from the beaker each time, until the blue litmus does not turn red – you have now used up all the acid (it is neutralised).

4) Pour the solution you have made into an evaporating dish. Heat the solution gently using a water bath. Be careful of a spitting solution!

5)Stop heating when crystals appear, DON'T let it boil dry. Allow to cool.

.

Writing the reaction

Acid + Alkali → Salt + Water

Can you write a word equation for our reaction we just carried out?

Can you write a symbol equation? Using the symbols below?

NaOH , HCl, H2O, NaCl

Writing the reaction

Acid + Alkali → Salt + Water

Can you write a word equation for our reaction we just carried out?

hydrochloric acid + sodium hydroxide → sodium chloride + water

Can you write a symbol equation? Using the symbols below?

HCl + NaOH → NaCl + H2O

Writing the reaction

Acid + Alkali → Salt + Water

Can you write a word equation for our reaction we just carried out?

hydrochloric acid + sodium hydroxide → sodium chloride + water

Can you write a symbol equation? Using the symbols below?

HCl + NaOH → NaCl + H2O

The H in the acid has been replaced by the metal.

Writing the reaction

Acid + Alkali → Salt + Water

You always make water.

The salt has 2 words and they depend on the acid and alkali used.

The salt gives us the surname:

hydrochloric acid makes a chloride

nitric acid makes a nitrate

sulfuric acid makes a sulfate

The metal in the alkali gives us the first name:

sodium hydroxide has sodium

To consolidate

8B41a – help to consolidate the naming of salts

8B41b – same reactions but some of the chemicals have already been placed.

8B4 2 – summary questions for the whole lesson.