how many molecules are in LYCRA and STARCH?
To determine the number of molecules in LYCRA and STARCH, we need to consider their chemical compositions and molar masses.
1. LYCRA:
LYCRA is a brand name for spandex, a synthetic polymer composed of a long-chain polymer called polyurethane. The molecular formula for polyurethane varies based on the specific type of LYCRA, but a common example is polyurethane with the repeating unit of C14H16N2O2.
To calculate the number of molecules in LYCRA, we need to know two things:
- The mass of the LYCRA sample in grams.
- The molar mass of polyurethane.
2. STARCH:
Starch is a complex carbohydrate composed of two types of glucose molecules: amylose and amylopectin. The molecular formula for glucose is C6H12O6.
To calculate the number of molecules in starch, we need to know:
- The mass of the starch sample in grams.
- The molar mass of glucose.
Once we have this information, we can use the following steps:
1. Determine the molar mass:
- Look up the molar mass of polyurethane and glucose. These values can typically be found in a chemistry reference book or through an online search.
- The molar mass is expressed in grams per mole (g/mol).
2. Calculate the number of moles:
- Divide the mass of LYCRA or starch sample in grams by the molar mass of the respective compound. This calculation gives you the number of moles.
3. Determine Avogadro's number:
- Avogadro's number is roughly 6.022 x 10^23, and it represents the number of particles (atoms, molecules, or ions) in one mole of a substance.
4. Calculate the number of molecules:
- Multiply the number of moles by Avogadro's number to find the number of molecules in LYCRA or starch.
Remember, the specific molar masses and sample masses are needed to obtain accurate results.