Procedure Label the five cupcake wrappers from 1 - 5. Each wrapper will hold one

Question

Procedure
Label the five cupcake wrappers from 1 - 5. Each wrapper will hold one of the following chemicals: 1 = Sucrose, 2 = Sodium chloride, 3 = Stearic acid, 4 = Corn starch, 5 = Sodium bicarbonate.
Put on a pair of gloves and goggles, and place a small pinch of each chemical into the corresponding wrapper. Be sure to wipe off your gloves on a paper towel between chemical samples to avoid crosscontamination.
Predict which compound you believe will melt first and record this in Table 3.
Fasten the ring on the ring stand, and cover the ring with foil to create a platform (rather than an open ring) to set the cupcake wrappers on. The ring should be positioned approximately 3 inches above the surface you are working on.
Place the first cupcake wrapper on the ring.
Remove the inner ring from the Heat Cell™, and use matches to carefully light the igniter fiber. Place the Heat Cell™ under the cupcake wrapper. Make sure that no flammable items (alcohol, paper, etc.) are located near the Heat Cell™. Flames should always be given extra attention. Please be very careful when working with flames, and never grab hot lab-ware with bare skin exposed.
Start a stopwatch, and record how long it takes the chemical to melt in Table 3. If a sample has not melted after two minutes, record it as “did not melt”.Note: The average temperature for a candle flame is approximately 1,000 °C. However, the exact temperature of the heat when it reaches your chemical will vary by altitude, room temperature, wick length, etc.
Use kitchen tongs to put the lid back on the Heat Cell™ to extinguish the flame. Allow the cupcake wrapper to cool down before handling.
Repeat Steps 5 - 8 with the remaining chemicals.
Based on the melting point order and information from the introduction, determine what type of bond the compound uses (ionic or covalent) and record your answers in Table 3.
Table 3: Melting Point Data
Prediction
Compound Name
Time the Compound Took to Melt
Melting Order (or, indicate if the compound did not melt)
Type of Bond
1st =
 
 
 
 
2nd =
 
 
 
 
3rd =
 
 
 
 
4th =
 
 
 
 
5th =
 
 
 
 

Explanation / Answer

1) Of the given five compounds, stearic acid is the one which melts faster , as it is polar covalent molecule with less hydrogen bonding. Though sucrose and starch are also cpolar covalent compounds, they have excessive hydrogen bonds and large number of polar hydroxyl groups.

2) Within two minutes sucrose and stearic acid melt and corn starch may decompose. However sodium chloride and sodium bicarbonate do not melt .

3) sucrose - polar covalent

    stearic acid - polar covalent

   NaCl -ionic

   sodium bicarbonate- ionic and covalent

corn starch - polymeric polar covalent

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