Tantangan Identifikasi Zat Tidak Dikenal

Menggunakan sifat fisika dan kimia untuk mengidentifikasi serbuk misterius

Qualitative Analysis Intermediate (High School) 75 menit ~$10,00

Tujuan

Terapkan beberapa uji kualitatif untuk mengidentifikasi serbuk putih yang tidak diketahui, mengembangkan keterampilan berpikir analitis sistematis.

Latar Belakang

This integrative experiment challenges students to identify unknown white powders from a set of possibilities (NaCl, NaHCO₃, CaCO₃, cornstarch, sugar, baking powder) using a battery of physical and chemical tests. Students must design their own testing sequence, demonstrating understanding of solubility, acid reactivity, flame tests, and indicator tests.

Peringatan Keselamatan

  • Do not taste any unknown samples
  • Wear goggles when heating or adding acid to unknowns
  • Some unknowns may react vigorously with acid

APD yang Diperlukan

goggles gloves lab_coat

Bahan

  • Unknown powders (3–5 samples) (2 g each)
    Labeled A, B, C, etc.
  • Dilute HCl (1M) (10 mL)
    For acid reactivity test
  • Distilled water (100 mL)
    For solubility test
  • Iodine solution (5 mL)
    Starch test
  • Universal indicator (5 mL)
    pH test
  • Cobalt chloride paper (5 strips)
    Water of crystallization test

Peralatan

Test tubes (10) Bunsen burner Nichrome wire loop Spatula Magnifying glass Evaporating dish

Prosedur

1

Observe each unknown's physical appearance under magnifying glass: crystal shape, texture, color. Record observations.

10 menit
2

Solubility test: Add 0.5 g of each unknown to 5 mL distilled water. Stir and observe if it dissolves, partially dissolves, or is insoluble.

10 menit
3

pH test: Add 2 drops of universal indicator to the dissolved/suspended samples. Record the pH.

5 menit
4

Acid reactivity: Add 5 drops of dilute HCl to a small amount of each dry unknown. Record any effervescence (CO₂ evolution).

10 menit
5

Iodine test: Add 2 drops of iodine solution to each unknown dissolved in water. Record color change.

5 menit
6

Flame test: Using a clean nichrome wire, test each unknown in the Bunsen burner flame.

15 menit Keep face away from flame
7

Heat test: Gently heat a small amount of each unknown in an evaporating dish. Observe melting, charring, or gas evolution.

10 menit Use tongs to handle hot dish
8

Compile all results and cross-reference to identify each unknown. Write your reasoning.

10 menit

Hasil yang Diharapkan

NaCl: soluble, neutral pH, no acid reaction, yellow flame. NaHCO₃: soluble, basic pH, effervesces with acid. CaCO₃: insoluble, effervesces with acid, orange-red flame. Cornstarch: insoluble, positive iodine test. Sugar: soluble, chars on heating.

Pembersihan

Dispose of acid-reacted solutions in waste container. Clean all test tubes and glassware. Return unused unknown samples.

Detail

Kategori
Qualitative Analysis
Tingkat Kesulitan
Intermediate (High School)
Durasi
75 menit
Perkiraan Biaya
$10,00
Langkah
8
Bahan
6

Eksperimen Lainnya

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Frequently Asked Questions

What is the objective of Tantangan Identifikasi Zat Tidak Dikenal?
Terapkan beberapa uji kualitatif untuk mengidentifikasi serbuk putih yang tidak diketahui, mengembangkan keterampilan berpikir analitis sistematis.
How difficult is Tantangan Identifikasi Zat Tidak Dikenal?
This experiment is rated as Intermediate (High School). It takes approximately 75 minutes to complete.
What safety precautions are needed for Tantangan Identifikasi Zat Tidak Dikenal?
Key safety precautions include: Do not taste any unknown samples; Wear goggles when heating or adding acid to unknowns; Some unknowns may react vigorously with acid.
What materials are needed for Tantangan Identifikasi Zat Tidak Dikenal?
The main materials required are: Unknown powders (3–5 samples), Dilute HCl (1M), Distilled water, Iodine solution, Universal indicator.
What results should I expect from Tantangan Identifikasi Zat Tidak Dikenal?
NaCl: soluble, neutral pH, no acid reaction, yellow flame. NaHCO₃: soluble, basic pH, effervesces with acid. CaCO₃: insoluble, effervesces with acid, orange-red flame. Cornstarch: insoluble, positive iodine test. Sugar: soluble, chars on heating.