Oxide – chemical compound which consists of two elements. One of oxide elements - oxygen. Oxides are classified by character on acid and the main. The acidity or basicity can be proved, knowing chemical properties of substances and to confirm knowledge with reactions in practice.
Instruction
1. Acid have properties oxides which in interaction with hydroxides form salts with water. Add the basis to the studied oxide. Received salt with water – oxide sour. CO ₂ + Ba(OH) ₂ →BaCO ₃↓ +H₂OSO ₃ + Ba(OH) ₂ →BaSO ₄↓ + H₂O
2. Acid oxides form with the main oxides of salt. Mix obviously known main oxide with estimated acid oxide. Received salt – oxide acid. CO ₂ + BaO →BaCO ₃↓ SO ₃ + BaO →BaSO ₄↓
3. Acid oxides, interacting with water, form acids. Flow in a test tube with oxide water, acid was formed – oxide was sour. If reaction took place without visible changes, lower a litmus piece of paper in a test tube. Acid paints litmus in red color.CO ₂ + H₂O → H₂CO ₃ (instantly decays) → CO ₂↑ + H₂OSO ₃ + H₂O → H₂SO ₄
4. Those oxides which at reaction with acids form water and salts have the main properties. Add to a test tube with oxide acid. Salt – oxide the main was formed. Na₂O + H₂SO ₄→ Na₂SO ₄ + H₂OBaO + H₂SO ₄→ BaSO ₄↓ + H₂O
5. The main oxides in interaction with acid form salt. Flow in a test tube with estimated main oxide some acid oxide, salt.NaO + by SO ₃ →Na₂SO₄CaO + SO ₃ → CaSO ₄↓ as a result has to be formed
6. With water the main oxides give hydroxides. Flow in a test tube with oxide water, slightly stir up and lower a litmus piece of paper. Blue color of litmus paper says that in a test tube the basis was formed, respectively, initial oxide was the main.NaO + H₂O →2 NaOHBaO + H₂O → Ba(OH) ₂
7. Amphoteric (transitional) oxides react both with acids and with the bases, at the same time they form salts. Divide solution with amphoteric oxide into two portions. To the first part flow alkali, add acid to the second. Salts were formed – the amphoteric character is proved. ZnO + H₂SO ₄→ ZnSO ₄ + H₂O ZnO + 2NaOH = Na₂ZnO ₂ + H₂O