period 3 [I2] PAPER 1 Flashcards

1
Q

reaction between sodium and water?

A

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

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2
Q

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.

A

temperature will go up more OR reactants can shoot out of the tube

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3
Q

reaction between magnesium and water?

A

with cold water:
Mg(s) + 2H2O(l) → Mg(OH)2 (aq) + H2(g)

with steam:
Mg(s) + H2O(g) → MgO(s) + H2(g)

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4
Q

reaction between sodium and oxygen - equation and observations?

A

• 4Na + O2 → 2Na2O
• orange flame
• white solid

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5
Q

reaction between magnesium and oxygen - equation and observations?

A
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6
Q

reaction between aluminium and oxygen - equation and observations?

A
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7
Q

reaction between silicon and oxygen - equation and observations?

A
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8
Q

reaction between phosphorus and excess oxygen - equation and observations?

A
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9
Q

reaction between sulfur and oxygen - equation and observations?

A
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10
Q

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.

A

• heat slowly in a thiele tube
• lower melting point indicates the presence of impurities

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11
Q

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.

A

• oxide ions react with water to form hydroxide ions
• sodium hydroxide is more soluble than magnesium hydroxide

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12
Q

reaction between phosphorus and limited oxygen - equation and observations?

A
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13
Q

structure of Na2O ?

A

ionic lattice

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14
Q

structure of MgO ?

A

ionic lattice

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15
Q

structure of Al2O3 ?

A

ionic lattice with covalent character (Al3+ distorts O2- electron cloud)

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16
Q

structure of SiO2 ?

A

giant covalent lattice

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17
Q

structure of P4O10 ?

A

simple covalent molecule

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18
Q

structure of SO2 / SO3 ?

A

simple covalent molecule

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19
Q

What is the trend in melting points for period 3 oxides (state highest and lowest and why and draw graph)?

A

• 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

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20
Q

Reaction of sodium oxide with water and pH?

A
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21
Q

reaction of magnesium oxide with water and pH?

A
22
Q

which period 3 oxides are basic?

A

Na2O and MgO

23
Q

Aluminium oxide is amphoteric. What is meant by this?

A

reacts with acids and bases (so, can act as both an acid or a base)

24
Q

is aluminium oxide soluble in water?

A

no

25
Q

is silicon dioxide soluble in water?

A

no

26
Q

reaction of phosphorus pentoxide with water and pH?

A

[from MS] pH: -1 to +1

27
Q

reaction of sulfur dioxide with water and pH?

A
28
Q

dissociation of the acid formed when P4O10 reacts with water?

A
29
Q

structure of H3PO4 ?

A
30
Q

reaction of SO2 with water and pH?

A
31
Q

reaction of SO3 with water and pH?

A
32
Q

structure of H2SO4 ?

A
33
Q

structure of H2SO3 ?

A
34
Q

Explain, in terms of crystal structure and bonding, why silicon (IV) oxide has a higher melting point than phosphorus (V) oxide.

A

• SiO2 is a giant covalent lattice
• strong covalent bonds between atoms (and need a lot of energy to overcome)
• P4O10 is a simple covalent molecule
• weak van der Waal’s forces between molecules (that break easily)

35
Q
A
36
Q

Give the formula of a hydroxide of an element in Period 3 used in medicine.

A

Mg(OH)2

37
Q

Identify the element in Period 3, from sodium to chlorine, that has the largest atomic radius.

A

sodium

38
Q
A

cross at 1580 (allow any cross between values for Mg and Al)

39
Q

Give an equation and one observation made for the reaction that occurs when phosphorus is heated in oxygen.

A
40
Q

Explain the increase in melting point from sodium oxide to magnesium oxide.

A

• increased charge density on magnesium ion
• stronger attraction between Mg2+ and O2– (so, stronger ionic bonding)

41
Q

Explain why the melting point of the oxide of silicon is much higher than that of the highest oxide of phosphorus.

A

• SiO2 is giant covalent
• P4O10 is simple molecular
• covalent bonds throughout structure of SiO2 are much stronger than the van der Waals forces between molecules in P4O10

42
Q

Describe a test you could carry out in a test tube to distinguish between sodium oxide and phosphorus oxide.

A

• react with water
• measure pH using litmus paper
• litmus paper is blue with sodium oxide and red with phosphorus oxide

43
Q
A

A

44
Q

Explain why silicon dioxide has a higher melting point than sulfur trioxide.

A

• SiO2 is giant covalent
• SO3 is simple molecular
• strong covalent bonds between atoms in SiO2
• van der Waal’s forces between molecules in SO3
• covalent bonds are stronger then van der Waal’s forces, so more energy is required to overcome covalent bonds

45
Q
A

D

46
Q

Explain why the atomic radii of the elements decrease across Period 3
from sodium to chlorine.

A

nuclear charge increases, so attraction between nucleus and electrons increase

47
Q

Explain why the melting point of sulfur (S8) is greater than that of phosphorus (P4).

A

• S8 molecules are bigger than P4 molecules
• so, van der Waal’s forces between molecules are stronger in sulfur

48
Q

Explain why sodium oxide forms an alkaline solution when it reacts with water.

A
49
Q

Write two equations to show the amphoteric nature of aluminium oxide.

A
(one from the top, one from the bottom)
50
Q
A

• oxide ions react with water to form hydroxide ions
• sodium hydroxide is more soluble than magnesium hydroxide

51
Q

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.

A
52
Q

Some sodium sulfate is dissolved into a solution containing NaHSO4. Explain why this increases the pH of the solution.

A