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Lithium, sodium and potassium all react with cold water - Edexcel - GCSE Chemistry - Question 5 - 2013 - Paper 1
Question 5
Lithium, sodium and potassium all react with cold water. (a) Lithium, sodium and potassium are in group 1 of the periodic table. Complete the sentence by putting a... show full transcript
Worked Solution & Example Answer:Lithium, sodium and potassium all react with cold water - Edexcel - GCSE Chemistry - Question 5 - 2013 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
Answer
The correct answer is D alkali metals. Lithium, sodium, and potassium are all alkali metals found in Group 1 of the periodic table. They are characterized by having one electron in their outer shell, which they readily lose in reactions, particularly with water.
Step 2
Explain why this happens.
Answer
When sodium is added to cold water, it forms a molten ball that floats on the surface due to its low density. The reaction between sodium and water produces hydrogen gas, which is trapped under the molten sodium, creating a dome effect. This gaseous hydrogen further aids in buoyancy, allowing the sodium to float. Additionally, the exothermic reaction generates enough heat to melt the sodium, causing it to take on a spherical shape.
Step 3