When chromium reacts with oxygen, chromium oxide is formed - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2021 - Paper 1
Question 2
When chromium reacts with oxygen, chromium oxide is formed.
(i) Write the word equation for this reaction.
(ii) What type of reaction occurs when chromium reacts w... show full transcript
Worked Solution & Example Answer:When chromium reacts with oxygen, chromium oxide is formed - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2021 - Paper 1
Step 1
Write the word equation for this reaction.
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Answer
The word equation for the reaction between chromium and oxygen is:
Chromium + Oxygen → Chromium Oxide
Step 2
What type of reaction occurs when chromium reacts with oxygen?
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Answer
The type of reaction that occurs when chromium reacts with oxygen is: D oxidation.
Step 3
Calculate the relative formula mass of chromium oxide, Cr₂O₃.
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Answer
To calculate the relative formula mass of Cr₂O₃, we sum the atomic masses of its components:
Chromium (Cr): 2 atoms × 52 = 104
Oxygen (O): 3 atoms × 16 = 48
Thus, the total relative formula mass is:
104+48=152
Step 4
Place the metals in order of reactivity from most to least reactive.
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Answer
The order of reactivity from most to least reactive is:
1. Magnesium → 2. Iron → 3. Silver
Step 5
What is the safest way to ignite the gas?
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The safest way to ignite the gas is: C put a lighted splint at the open end of the test tube.
Step 6
State the observation made in this test that shows that the gas is hydrogen.
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The observation that indicates the gas is hydrogen is: a distinct 'pop' sound is heard when the gas is ignited.
Step 7
State why iron can be extracted by heating iron oxide with carbon.
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Answer
Iron can be extracted by heating iron oxide with carbon because:
Carbon reduces iron oxide to iron by removing the oxygen, resulting in the formation of carbon dioxide.
Step 8
State why electrolysis is not used to extract iron.
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Electrolysis is not used to extract iron because:
It is not economically viable due to the high energy costs associated with the process.
