period 3 [I2] PAPER 1 Flashcards
reaction between sodium and water?
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
When a piece of sodium is added to 200 cm3 of water in a large beaker a vigorous reaction occurs. The temperature of the water increases by 25 °C.
Suggest why it is dangerous to react a similar piece of sodium with 10 cm3 of water in a boiling tube.
temperature will go up more OR reactants can shoot out of the tube
reaction between magnesium and water?
with cold water:
Mg(s) + 2H2O(l) → Mg(OH)2 (aq) + H2(g)
with steam:
Mg(s) + H2O(g) → MgO(s) + H2(g)
reaction between sodium and oxygen - equation and observations?
• 4Na + O2 → 2Na2O
• orange flame
• white solid
reaction between magnesium and oxygen - equation and observations?
reaction between aluminium and oxygen - equation and observations?
reaction between silicon and oxygen - equation and observations?
reaction between phosphorus and excess oxygen - equation and observations?
reaction between sulfur and oxygen - equation and observations?
A sample of the highest oxide of phosphorus was prepared in a laboratory.
Describe a method for determining the melting point of the sample. State how the result obtained could be used to evaluate its purity.
• heat slowly in a thiele tube
• lower melting point indicates the presence of impurities
Sodium oxide forms a solution with a higher pH than magnesium oxide when equal amounts, in moles, of each oxide are added separately to equal volumes of water.
State why both oxides form alkaline solutions.
Suggest why sodium oxide forms a solution with a higher pH than the solution formed from magnesium oxide.
• oxide ions react with water to form hydroxide ions
• sodium hydroxide is more soluble than magnesium hydroxide
reaction between phosphorus and limited oxygen - equation and observations?
structure of Na2O ?
ionic lattice
structure of MgO ?
ionic lattice
structure of Al2O3 ?
ionic lattice with covalent character (Al3+ distorts O2- electron cloud)
structure of SiO2 ?
giant covalent lattice
structure of P4O10 ?
simple covalent molecule
structure of SO2 / SO3 ?
simple covalent molecule
What is the trend in melting points for period 3 oxides (state highest and lowest and why and draw graph)?
• MgO = highest, SO2 = lowest
• increases along group for metals due to strong ionic bonding, but Al2O3 is lower due to covalent character
• decreases with size for simple covalent molecules
Reaction of sodium oxide with water and pH?