This question is about some Period 3 elements and their oxides - AQA - A-Level Chemistry - Question 6 - 2017 - Paper 1
Question 6
This question is about some Period 3 elements and their oxides.
1. Write an equation for the reaction of phosphorus with an excess of oxygen.
2. Describe a test yo... show full transcript
Worked Solution & Example Answer:This question is about some Period 3 elements and their oxides - AQA - A-Level Chemistry - Question 6 - 2017 - Paper 1
Step 1
Write an equation for the reaction of phosphorus with an excess of oxygen.
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Answer
The balanced equation for the reaction is:
4P+5O2​→2P2​O5​
Step 2
Describe a test you could carry out in a test tube to distinguish between sodium oxide and the product of the reaction in Question 6.1.
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Answer
To distinguish between sodium oxide and phosphorus pentoxide, add a universal indicator or pH meter to both substances dissolved in water. Sodium oxide will result in a basic solution (pH > 7), while phosphorus pentoxide will yield an acidic solution (pH < 7).
Step 3
State the type of crystal structure shown in silicon dioxide and sulfur trioxide.
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Explain why silicon dioxide has a higher melting point than sulfur trioxide.
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Answer
Silicon dioxide has a higher melting point due to its giant covalent structure, which involves strong covalent bonds between atoms requiring more energy to break. In contrast, sulfur trioxide has a molecular structure that is held together by weaker van der Waals forces, which take less energy to overcome.
Step 5
Write an equation for the reaction of sulfur trioxide with potassium hydroxide solution.
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Answer
The balanced equation for the reaction is:
SO3​+2KOH→K2​SO4​+H2​O
Step 6
Write an equation for the reaction of an excess of magnesium oxide with phosphoric acid.
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Answer
The balanced equation for the reaction is:
3MgO+2H3​PO4​→Mg3​(PO4​)2​+3H2​O
Step 7
Draw the displayed formula of the undissociated acid formed when sulfur dioxide reacts with water.
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Answer
The displayed formula of sulfurous acid formed is:
