Period 3 Oxides Flashcards
Describe what you would observe when sodium reacts with water
Vigorous reaction
Fizzing
Floating on water
Movement on water
Why does sodium float on water?
Because it’s less dense
Is the reaction between sodium and water endo or exothermic?
Exothermic
Give the molecular equation of sodium and water
2Na + 2H2O —-> 2NaOH + H2
What is the pH of the solution formed from sodium and water?
Alkaline
Describe what you would observe when magnesium reacts with cold water
Slow reaction
Give the molecular equation of magnesium and cold water
Mg + 2H2O —> Mg(OH)2 + H2
What state is the magnesium hydroxide in when it’s formed from magnesium and cold water?
As a thin layer on the magnesium
Describe what you would observe when magnesium reacts with steam?
Vigorous reaction
White light
Produces white solid
Give the molecular equation of magnesium and steam
Mg + H2O (g) —-> MgO + H2
How would you set up a reaction of magnesium and steam?
Put test tube into a clamp with damp cotton wool and magnesium
Attach delivery tube to test tube and upturned glass tube/measuring cylinder under water in trough of water
Heat to produce steam
Give the equation of sodium and oxygen
4Na + O2 —> 2Na2O
What is observed when sodium and oxygen react
Burns with a yellow flame
Forms white solid of Na2O
Is sodium oxide acidic, basic or amphoteric?
Basic
What is the bonding in sodium oxide and explain how this relates to its properties
Giant ionic lattice - gives it a high melting point
Give the equation for the reaction of magnesium and oxygen
2Mg + O2 —> 2MgO
Describe what you would observe in the reaction of magnesium and oxygen
Burns with a white flame to produce a white solid
Is magnesium oxide basic, acidic or amphoteric?
Basic
What is the bonding in magnesium oxide and explain how this relates to its properties
Giant ionic lattice - high melting point
Give the equation for the reaction of aluminium and oxygen
4Al + 3O2 —> 2Al2O3
Describe what you would see when aluminium and oxygen react
Burns with a white flame to produce a white solid
Is aluminium acidic, basic or amphoteric
Amphoteric
What is the bonding in aluminium oxide?
Ionic, but because of the high charges on the ions they polarise and the compound has some covalent character
In what form does aluminium react best and why?
In the powdered form bc as foil, a passive protective oxide layer prevents reaction
Give the equation for the reaction of silicon and oxygen
Si + O2 —-> SiO2
What are the conditions for the reaction of silicon and oxygen?
Heated strongly
What kind of bonding does silicon dioxide have?
Covalent - macromolecular
Is silicon dioxide acidic, amphoteric or basic?
Acidic
What are the formulae of the two oxides of sulfur dioxide?
SO2 and SO3
Give the equations which form the two oxides of sulfur
S + O2 —> SO2
2SO2 + O2 —- 2SO3
Describe what you would see when sulfur reacts with oxygen
Yellow solid sulfur melts to a red liquid which burns with a blue flame
What is the trend in bonding across period 3?
Gets more covalent
Goes from giant ionic to molecular covalent
What is the trend in melting point across period 3?
Melting point decreases bc lower Mr and weaker bonding so less energy needed to break the intermolecular forces + bonds