Copper Sulfate (slow motion) - Periodic Table of Videos

TL;DR

Copper and ammonia react to form a pale blue precipitate, which then turns into a deep blue color due to the formation of coordination complexes.

Transcript

now i've seen this reaction lots of times but this is the first time i've seen it in high speed where we pour the solution in quite slowly but then watch what happens the reaction of copper with ammonia is quite a well-known reaction and often students school children come across it quite early on in their career it's a reaction which gives both a ... Read More

Key Insights

• 💙 The copper and ammonia reaction results in a visually striking color change from pale blue to dark blue.
• 💁 The formation of coordination complexes between copper ions and ammonia molecules leads to the intense blue color.
• 🫥 The delay in the appearance of the dark blue color may be attributed to the growth of visible precipitate crystals.
• 🎓 The reaction is a common demonstration in chemistry education due to its visual appeal and scientific significance.
• 🔹 Small crystallites initially formed in the reaction may be too small to be visible, leading to the delayed appearance of the dark blue color.
• 😑 The coordination of ammonia molecules with copper ions results in a tetrahedral shape, enhancing the intensity of the blue color.
• 💁 The demonstration highlights the concept of complex formation and color changes in coordination chemistry.

Questions & Answers

Q: What is the initial reaction between copper sulfate and ammonia?

The initial reaction results in a pale blue precipitate of copper hydroxide and copper sulfate when ammonia is added to copper sulfate solution.

Q: Why does the color change from pale blue to dark blue as more ammonia is added?

The color change occurs due to the formation of coordination complexes where ammonia molecules bind to copper ions, resulting in a deep blue color.

Q: Why does the dark blue color appear before the precipitate forms in the reaction?

The delay in the appearance of the dark blue color may be due to the slow growth of the precipitate crystals, which become visible as they grow larger than the wavelength of light.

Q: How does the reaction between copper and ammonia demonstrate coordination complexes?

The reaction showcases how stable molecules like ammonia can bind to copper ions, forming coordination complexes that exhibit distinctive color changes.

Summary & Key Takeaways

• Copper sulfate reacts with ammonia to form a pale blue precipitate of copper hydroxide and copper sulfate.

• As more ammonia is added, the precipitate redissolves, resulting in a deep blue color due to the formation of coordination complexes.

• The color change from pale blue to dark blue is visually captivating and demonstrates the formation of stable coordination complexes.