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When lithium is placed in water it reacts to form lithium hydroxide and hydrogen gas - Edexcel - GCSE Chemistry - Question 5 - 2016 - Paper 1
Question 5
When lithium is placed in water it reacts to form lithium hydroxide and hydrogen gas. Describe what you would see during this reaction. The following hazard symbol... show full transcript
Worked Solution & Example Answer:When lithium is placed in water it reacts to form lithium hydroxide and hydrogen gas - Edexcel - GCSE Chemistry - Question 5 - 2016 - Paper 1
Step 1
When lithium is placed in water it reacts to form lithium hydroxide and hydrogen gas. Describe what you would see during this reaction.
Answer
During the reaction, you would see bubbles of hydrogen gas being produced. The lithium would float on the surface of the water and may produce a small flame or fizzing sound due to the hydrogen gas escaping.
Step 2
Step 3
They both conduct electricity. Explain, in terms of their structures, how metals conduct electricity.
Answer
Metals conduct electricity due to the presence of free-moving electrons in their structure. In metallic bonding, atoms are closely packed in a lattice structure and can release some of their outer electrons, allowing them to move freely throughout the metal. This movement of electrons enables the conduction of electric current.
Step 4
State a difference in the appearance of magnesium salts and iron salts.
Answer
Magnesium salts are typically colorless or white when dissolved in water, while iron salts often have a distinct color; for example, iron (II) salts are usually pale green, whereas iron (III) salts can appear yellow or brown.
Step 5
Describe and explain what you would see in each of these three reactions and what it would tell you about the relative reactivity of the halogens, bromine and iodine.
Answer
In the reaction with potassium chloride and chlorine, no reaction would occur, indicating that chlorine is less reactive than iodine. With potassium bromide and bromine, a reaction would occur, suggesting that bromine is more reactive than iodine. Finally, in the reaction with potassium iodide, again no reaction would be observed, suggesting that iodine is the least reactive of the three halogens. This indicates that chlorine is the most reactive, followed by bromine, and then iodine.