๐Ÿ“˜ CodingMarble Learn

Genetic Links Between Substances

Substances are related like a family tree. A metal burns to a basic oxide, the oxide meets water to give a base. A non-metal burns to an acidic oxide, which meets water to give an acid. A base and an acid react to give a salt and water. Organic substances join this web too: they burn to CO2 and water, and plants turn CO2 back into organic matter.

๐ŸŽฌ Step-by-step story

  1. Two starting substances. Top row: a metal, calcium. Bottom row: a non-metal, carbon.
  2. Both burn in oxygen. The metal makes a basic oxide, CaO. The non-metal makes an acidic oxide, CO2.
  3. Add water. CaO becomes a base, Ca(OH)2. CO2 becomes an acid, H2CO3.
  4. The base and the acid meet. They make a salt, CaCO3, and water. Both rows join here.
  5. Sugar is organic. Burn it and you get CO2. Plants take CO2 and make sugar again. The loop closes.
  6. Your turn. Pick any metal and any non-metal and see which salt they can make.

Tip: drag the 3D scene to turn it. Use two fingers to zoom.

๐Ÿค” Common doubts, cleared

Is the starting metal a pure element?

Yes. Calcium in the 3D is the simple substance. Real calcium reacts very fast, so it is stored away from air.

Why does a metal give a basic oxide and a non-metal an acidic one?

Metal oxides like to take hydrogen ions (basic); non-metal oxides give hydrogen ions in water (acidic). Watch the two rows split at step 1.

Does every oxide become a base or acid with water?

No. CuO and SiO2 do not react with water. Calcium and sodium oxides do, as the 3D shows.

Why do two different rows end in one salt?

A salt needs both parts: a metal part (from the base) and an acid part (from the acid). Only the meeting gives a salt.

How can a living thing like sugar be linked to CO2?

Sugar is made of carbon, hydrogen and oxygen. Burning or breathing breaks it into CO2 and water, and plants rebuild it.

Can I get a different salt?

Yes. Change the metal or the non-metal in the free play and the salt name changes: CaCO3, CaSO4, Na2CO3 or Na2SO4.

The main classes of inorganic substances

A simple substance has one kind of atom: a metal (Ca, Na, Mg) or a non-metal (C, S, O2).

A compound has two or more kinds of atoms. The main classes are:

What is a genetic link?

"Genetic" here does not mean genes. It means born from. A genetic link says: this substance can be made from that one. Write them in a row and you get a genetic series.

Metal series: Ca โ†’ CaO โ†’ Ca(OH)2 โ†’ CaCO3

Non-metal series: C โ†’ CO2 โ†’ H2CO3 โ†’ CaCO3

Notice that the two series meet in a salt.

Step by step: the equations

  1. Metal + oxygen โ†’ basic oxide: 2Ca + O2 โ†’ 2CaO
  2. Basic oxide + water โ†’ base: CaO + H2O โ†’ Ca(OH)2
  3. Non-metal + oxygen โ†’ acidic oxide: C + O2 โ†’ CO2
  4. Acidic oxide + water โ†’ acid: CO2 + H2O โ‡Œ H2CO3
  5. Base + acid โ†’ salt + water: Ca(OH)2 + H2CO3 โ†’ CaCO3 + 2H2O

Shortcuts also exist: basic oxide + acid โ†’ salt + water, and base + acidic oxide โ†’ salt + water. Only metals that give a base soluble in water (like Na, K, Ca) can use the water step; for others (like Cu) the base is made from a salt with an alkali.

Other ways to reach a salt

A salt can also be made by: metal + acid (Zn + 2HCl โ†’ ZnCl2 + H2), metal + non-metal (2Na + Cl2 โ†’ 2NaCl), or salt + salt in solution (a new salt appears when one product is insoluble). Each is one more link in the web.

Organic and inorganic are linked too

Organic compounds are built on carbon chains: hydrocarbons, alcohols, acids, sugars, and so on. They are not a separate world. Burn any of them and you get inorganic CO2 and H2O. Plants do the reverse in photosynthesis: 6CO2 + 6H2O โ†’ C6H12O6 + 6O2. Carbon keeps moving between living and non-living things.

Key formulas and definitions

Worked examples

1. Write the genetic series of sodium to sodium sulfate.

Na โ†’ Na2O โ†’ NaOH โ†’ Na2SO4. Steps: 4Na + O2 โ†’ 2Na2O; Na2O + H2O โ†’ 2NaOH; 2NaOH + H2SO4 โ†’ Na2SO4 + 2H2O.

2. Write the series of sulfur to sulfuric acid.

S โ†’ SO2 โ†’ SO3 โ†’ H2SO4. S + O2 โ†’ SO2; 2SO2 + O2 โ†’ 2SO3; SO3 + H2O โ†’ H2SO4.

3. Which two substances give calcium sulfate in one step?

Calcium hydroxide and sulfuric acid: Ca(OH)2 + H2SO4 โ†’ CaSO4 + 2H2O. Also CaO + H2SO4 โ†’ CaSO4 + H2O.

4. Burning 12 g of carbon fully gives how much CO2? (C = 12, O = 16)

C + O2 โ†’ CO2. 12 g C is 1 mole, giving 1 mole CO2 = 44 g.

5. Complete the chain: Mg โ†’ ? โ†’ Mg(OH)2 โ†’ MgCl2

Mg โ†’ MgO โ†’ Mg(OH)2 โ†’ MgCl2. 2Mg + O2 โ†’ 2MgO; MgO + H2O โ†’ Mg(OH)2 (slowly); Mg(OH)2 + 2HCl โ†’ MgCl2 + 2H2O.

6. Copper oxide does not react with water. How do we reach Cu(OH)2 from CuO?

Go through a salt: CuO + 2HCl โ†’ CuCl2 + H2O, then CuCl2 + 2NaOH โ†’ Cu(OH)2 (blue solid) + 2NaCl.

Common mistakes

Practice quiz

1. A metal burns in oxygen. The product is usually a:
2. CO2 dissolved in water gives:
3. Base + acid gives:
4. Which is the correct series?
5. Organic matter burns to give:

Practice: answer these yourself

Type or choose your answer, then press Check. Use a hint if you are stuck; the full solution appears after you answer.

Frequently asked questions

What does genetic link mean in chemistry?

It means one substance can be made from another. A row of such links, like metal, oxide, base, salt, is a genetic series.

Do all metals follow this chain?

Most reach an oxide. Only some oxides dissolve in water to give a base (Na, K, Ca). Others reach their base through a salt and an alkali.

Is a genetic link the same as heredity in biology?

No. Here "genetic" means "origin". It has nothing to do with genes or DNA.

Learn first

Learn next

Related lessons

All Chemistry lessons