Period Three Elements Flashcards
How does Na react with water? Give an equation.
- Sodium reacts with cold water.
- It shows effervescence on the surface.
- 2Na(s) + 2H2O(l) —> 2NaOH(aq) + H2(g)
How does Mg react with cold water and with steam? Give 2 equations
- Magnesium reacts very slowly with cold water to form the hydroxide but reacts more readily with steam to form the oxide.
- Mg + 2H2O —> Mg(OH)2 + H2
- Mg + H2O —> MgO + H2
What are the observations for the period 3 elements reacting with oxygen? (Up to S)
- Na burns with a yellow flame to produce a white solid.
- Mg, Al, Si, P burns with a white flame to give a white solid and smoke.
- S burns with a blue flame to form an acidic choking gas.
Give an equation for the reaction of sodium and oxygen?
4Na(s) + O2(g) —> 2Na2O(s)
Give an equation for the reaction of Mg and O2?
2Mg(s) + O2(g) —> 2MgO(s)
Give an equation for the reaction of Al and O2?
4Al(s) + 3O2(s) —> 2Al2O3(s)
Give an equation for the reaction of Si and O2?
Si(s) + O2(g) —> SiO2(s)
Give an equation for the reaction of phosphorous with oxygen?
4P(s) + 5O2(g) —> P4O10(s)
Give an equation for the reaction of S and O2?
S(s) + O2(g) —> SO2(g)
Why is Na stored under oil and P under water?
Prevent the element coming into contact with and therefore reacting with oxygen?
How does the period three metal ionic oxide sodium oxide react with water? Give an equation and suggest a pH value.
Sodium oxide:
- vigorous exoteric reaction
- Na2O(s) + H2O(l) —> 2Na+(aq) + 2OH-(aq)
- pH = 13/14
How does the period three metal ionic oxide magnesium oxide react with water? Give an equation and suggest a pH value.
Magnesium oxide:
- MgO(s) + H2O(l) —> Mg(OH)2(s)
- pH = 9
How does the period three metal ionic oxide aluminium oxide react with water? Give an equation and suggest a pH value.
Aluminium oxide:
- Does not dissolve in water due to high strength of the lattice
- pH = 7
Why does Mg(OH)2 have lower pH than NaOH in solution?
Mg(OH)2 is only slightly soluble in water as it’s lattice is stronger.
Hence, it dissolved less. There are fewer free OH- ions produced.
Lower pH.
How does SiO2 react with water? What is the pH of the products?
It does not dissolve in water due to it’s macromolecular structure.
pH = 7
How does the period three non-metal oxide phosphorus oxide react with water?
P4O10(s) + 6H2O(l) —> 4H3PO4(aq)
pH = 0
How do the period three non-metal sulphur oxides react with water?
Acidic solutions formed
SO2(g) + H2O(l) —> H2SO3(aq)
SO3(g) + H2O(l) —> H2SO4(aq)
Give the equation for the reaction of sodium oxide and hydrochloric acid?
Na2O(s) + 2HCL(aq) —> 2NaCl(aq) + H2O(l)
Give the equation for the reaction of magnesium oxide and hydrochloric acid?
MgO(s) + 2HCl(aq) —> MgCl2(aq) + H2O(l)
Give an equation for the equation of sodium hydroxide with sulfuric acid?
Na2O(s) + H2SO4(aq) —> Na2SO4(aq) + H2O(l)
Give an equation for the reaction of aluminium oxide and sulfuric acid?
Al2O3(s) + 3H2SO4(aq) —> Al2(SO4)3(aq) + 3H2O(l)
Give an equation for the reaction between Al2O3 and NaOH?
Al2O3(s) + 2NaOH(aq) + 3H2O(l) —> 2NaAl(OH)4
Give an equation for the reaction of SiO2 with NaOH?
2NaOH + SiO2 —> Na2SiO3 + H2O
Give an equation for the reaction of phosphorous oxide and sodium hydroxide?
P4O10(s) + 12NaOH(aq) —> 4Na3PO4(aq) + 6H2O(l)
