Aspartame is an artificial sweetener that is commonly used as a sugar substitute in foods and beverages. It is roughly 200 times sweeter than sugar and contains only a small amount of calories. Aspartame is composed of two amino acids, aspartic acid and phenylalanine, bound together by a methyl ester group. The chemical formula for aspartame is C14H18N2O5. In this article, we will calculate the number of moles of aspartame molecules present in 10g of aspartame.
Molar Mass of Aspartame
To calculate the number of moles, we first need to know the molar mass of aspartame. Molar mass is the mass of one mole of a substance, measured in grams per mole. It can be calculated by summing the atomic weights of each element in the chemical formula, taking their frequency into account.
The molar mass of aspartame is:
| Element | Atomic Weight | Frequency | Total Weight |
| C | 12.011 g/mol | 14 | 168.154 g/mol |
| H | 1.008 g/mol | 18 | 18.144 g/mol |
| N | 14.007 g/mol | 2 | 28.014 g/mol |
| O | 15.999 g/mol | 5 | 79.995 g/mol |
| Total | 294.307 g/mol |
Therefore, the molar mass of aspartame is 294.307 g/mol.
Moles of Aspartame
Now that we know the molar mass of aspartame, we can calculate the number of moles present in 10g using the formula:
Number of moles = Mass (g) / Molar mass (g/mol)
For 10g of aspartame:
Number of moles = 10g / 294.307 g/mol = 0.03399 moles
Therefore, there are 0.03399 moles of aspartame molecules in 10g of aspartame.
Molecules per Mole
To convert moles to molecules, we need to know Avogadro’s number which is 6.022 x 1023 molecules per mole. This is a constant that relates the number of molecules to the number of moles.
Using Avogadro’s number, we can calculate the number of aspartame molecules as:
Molecules = Moles x Avogadro’s number
For 0.03399 moles of aspartame:
Molecules = 0.03399 moles x (6.022 x 1023 molecules/mole)
= 2.046 x 1022 aspartame molecules
Therefore, there are 2.046 x 1022 aspartame molecules in 10g of aspartame.
Conclusion
In summary:
– The molar mass of aspartame is 294.307 g/mol
– There are 0.03399 moles of aspartame in 10g of aspartame
– Using Avogadro’s number, this equates to 2.046 x 1022 aspartame molecules
So for the original question “How many moles of molecules are in 10g of Aspartame?”, the answer is 0.03399 moles which corresponds to 2.046 x 1022 aspartame molecules.
Key Points
– Found the molar mass of aspartame to be 294.307 g/mol
– Used the molar mass to calculate the number of moles in 10g of aspartame
– Converted moles to molecules using Avogadro’s number
– Determined there are 0.03399 moles and 2.046 x 1022 molecules in 10g of aspartame
This step-by-step calculation demonstrates how to find the number of moles and molecules for a given mass of a chemical compound. Using the chemical formula, molar mass, and Avogadro’s number allows us to interconvert between mass, moles, and molecules. Understanding these fundamental relationships is key for many stoichiometry and chemistry calculations.
Background on Aspartame
Aspartame was first synthesized in 1965 and approved for use in food products in the 1980s. It is composed of two amino acids, phenylalanine and aspartic acid, bound together by a methyl ester group. When digested, aspartame breaks down into these amino acids and methanol. The phenylalanine and aspartic acid are used by the body while the methanol is converted to formaldehyde and formic acid.
While aspartame has been deemed safe for human consumption by regulatory agencies, there has been some controversy around its health effects. A small subset of people report neurological or behavioral reactions to aspartame, likely caused by phenylalanine buildup. There are also concerns around carcinogenicity due to the methanol breakdown product. However, extensive reviews have found no conclusive evidence of harm at typical exposure levels.
Overall, aspartame remains a very popular artificial sweetener, providing sweet taste with minimal caloric content. It is approximately 200 times sweeter than sucrose and retains its sweetness even at high temperatures, making it versatile for use in baked goods, beverages, desserts, and other foods. The acceptable daily intake (ADI) is set at 50 mg/kg body weight per day. Within this limit, it can be safely enjoyed as part of an overall healthy diet.
Chemical Structure
The chemical structure of aspartame consists of:
– Phenylalanine – contains a phenyl group (C6H5-) bound to an amino group (-NH2). The phenyl group provides the compound with an aromatic ring structure.
– Aspartic acid – contains a carboxylic acid group (-COOH) bound to an amino group (-NH2). The carboxyl group has deprotonated to form a negatively charged carboxylate group under normal pH conditions.
– Methyl ester – connects the phenylalanine and aspartic acid together through an ester bond (-COOCH3). This consists of a methyl group (CH3-) bound to a carbonyl oxygen.
The aspartic acid component and phenylalanine component are both amino acids that link together by condensing the carboxyl group of aspartic acid with the amino group of phenylalanine. This forms an amide bond. The methyl ester forms through the reaction of methanol with the carboxyl group on the aspartic acid side chain.
Key Functional Groups
– Amino group (-NH2) – provides basicity
– Carboxylic acid group (-COOH) – provides acidity, deprotonates into carboxylate group (-COO-)
– Ester bond (-COOCH3) – joins the phenylalanine and aspartic acid components
– Phenyl ring (C6H5-) – provides aromatic character
The combination of these functional groups gives aspartame its sweet taste and solubility properties. The amine and acid groups allow it to detect sweetness receptors on the tongue.
Synthesis of Aspartame
Aspartame is synthesized through the reaction between L-aspartic acid and L-phenylalanine methyl ester under alkaline conditions. This is a condensation reaction that forms a dipeptide with loss of a water molecule.
The key steps in the synthesis are:
1. L-phenylalanine is esterified using methanol to form L-phenylalanine methyl ester.
2. L-aspartic acid and L-phenylalanine methyl ester are combined under alkaline conditions, usually using sodium hydroxide.
3. The alpha-amine of phenylalanine performs a nucleophilic attack on the gamma-carboxyl carbon of aspartic acid. This forms a tetrahedral intermediate.
4. The hydroxyl group from the tetrahedral intermediate is lost as water, forming the amide bond between phenylalanine and aspartic acid.
5. The resulting aspartame dipeptide is purified through recrystallization.
Under the alkaline conditions, the amine group of phenylalanine is deprotonated making it a stronger nucleophile. The carboxyl group of aspartic acid also deprotonates into the carboxylate anion. This allows the amine to attack the carbonyl carbon, displacing the hydroxyl group and forming the amide bond.
Controlling factors like pH, temperature, and solvent allows high yields of aspartame to be produced. The final product is a white crystalline solid with a sweet taste estimated to be 200 times sweeter than sucrose.
Degradation of Aspartame
Although aspartame is stable at room temperature, it can degrade under certain conditions:
– **Elevated temperature** – Aspartame undergoes hydrolysis at high temperatures above 100°C. This causes it to lose its sweetness and break down into byproducts.
– **Changes in pH** – In very acidic or very alkaline environments, the amide bond in aspartame can hydrolyze. This will lead to methyaldehyde and a dipeptide of phenylalanine and aspartic acid.
– **Prolonged storage** – Over time, even at room temperature, aspartame slowly decomposes into components like diketopiperazine and its constituent amino acids.
The major degradation products of aspartame include:
– Phenylalanine
– Aspartic acid
– Methanol
– Diketopiperazine
Diketopiperazine results from the cyclization of the dipeptide backbone of aspartame. Methanol occurs from hydrolysis of the methyl ester.
To help prevent degradation, aspartame is often microencapsulated to protect it from moisture and temperature changes during storage and use. The sweetness and stability can also be enhanced by combining it with other non-nutritive sweeteners like acesulfame potassium.
Metabolism of Aspartame
When aspartame is consumed, it is completely metabolized in the digestive tract. It does not enter the bloodstream intact like sucrose would. Instead, it is hydrolyzed into its constituent components:
In the small intestine:
– Phenylalanine
– Aspartic acid
– Methanol
In the liver:
– Methanol is converted to formaldehyde and then to formic acid
The phenylalanine and aspartic acid are amino acids that are incorporated into proteins or used for energy. The methanol is processed by alcohol dehydrogenase and converted first to formaldehyde and then completely to formic acid.
Formic acid is either excreted in urine or broken down to carbon dioxide and water. There are no toxicity issues with phenylalanine, aspartic acid, or formic acid at the low levels produced from typical aspartame consumption.
However, those with the rare genetic disorder phenylketonuria (PKU) cannot properly metabolize phenylalanine. They must control their intake from all dietary sources. For these individuals, consumption of aspartame needs to be restricted.
Commercial Uses
Aspartame is one of the most widely used high intensity sweeteners in the food industry. Some of its major commercial applications include:
– **Soft drinks** – Aspartame is heat stable, making it suitable for use in diet sodas and other carbonated beverages. It enhances sweetness without altering the base flavor profile.
– **Yogurt** – Aspartame sweetens yogurt without adding the glycemic impact of sugar. It enhances the tart, tangy flavors consumers expect in yogurt.
– **Tabletop sweeteners** – Aspartame is frequently blended with other sweeteners like acesulfame potassium in tabletop sweetener packets and zero-calorie drink mix powders.
– **Baked goods** – Aspartame can be incorporated into sweeter baked goods like cakes, cookies, and bars to reduce sugar and calories. However, its stability decreases with prolonged heating, so use levels tend to be lower.
– **Frozen desserts** – Aspartame adds sweetness to items like low-calorie ice cream, sherbets, and fruit-based sorbets without the need for sugar.
– **Chewing gum** – Aspartame provides an exceptionally high level of sweetness in gum products. It complements and enhances fruit and mint flavors popular in chewing gum.
The high potency sweetness allows aspartame to be used at low concentrations. This keeps the calorie and carbohydrate contribution minimal while still providing sweetness for consumer acceptance.
Safety Controversies
While many regulatory agencies have ruled that aspartame is safe for human consumption, some controversy lingers over its potential health effects:
– **Carcinogenicity** – Some animal studies have found increased rates of cancers after consuming very high doses of aspartame. However, human epidemiological studies have found no conclusive evidence of increased cancer risk.
– **Neurotoxicity** – High doses of aspartame have been associated with headache, dizziness, mood changes, and other neurological symptoms in small subsets of people. It has been suggested that the methanol component may be responsible, but most experts have ruled out neurotoxic effects at typical exposure levels.
– **Phenylalanine effects** – Individuals with the rare condition PKU need to avoid phenylalanine from all sources, including aspartame. In healthy individuals, there is no evidence that phenylalanine from aspartame causes adverse effects.
– **Weight gain** – Some claim that aspartame increases appetite and leads to weight gain. However, numerous controlled trials found that substituting aspartame for sugar reduces total calorie intake without affecting body weight.
Overall, the majority of evidence indicates aspartame is safe at current acceptable daily intake levels. But some people may wish to moderate their individual consumption or avoid aspartame if they experience negative symptoms. As with any food additive, appropriate safety measures should continue to be taken.
Frequently Asked Questions
Q: What exactly is aspartame made of?
A: Aspartame is made of two amino acids, phenylalanine and aspartic acid, bound together by a methyl ester group. The chemical structure has a peptide bond between phenylalanine and aspartic acid, with methanol forming the methyl ester linkage.
Q: Is aspartame natural or artificial?
A: Aspartame is an artificial sweetener. While it contains two naturally occurring amino acids, aspartame itself does not occur in nature and is chemically synthesized.
Q: Does aspartame have any calories?
A: Despite its intense sweetness, aspartame has minimal calories. Each gram provides approximately 4 calories, compared to 16 calories per gram for sucrose. But since it is used at much lower concentrations for sweetening, the calorie contribution is negligible.
Q: Is aspartame safe?
A: Yes, decades of scientific research and review by regulatory agencies have concluded that aspartame is safe for human consumption at current approved intake levels for the general population. A small subset of people with PKU need to restrict phenylalanine from all sources.
Q: Can aspartame cause cancer?
A: No conclusive evidence from human studies shows that aspartame causes cancer. While animal studies at extremely high doses have raised concern, human epidemiological data does not indicate increased cancer risk under real-world consumption levels.
Conclusion
In conclusion, calculating the moles and molecules in a given mass of a substance requires knowing its molar mass and Avogadro’s number. For 10g of the artificial sweetener aspartame, we found there are 0.03399 moles and 2.046 x 1022 molecules. This required first finding the molar mass of aspartame based on its chemical formula, C14H18N2O5.
Aspartame provides a high level of sweetness with minimal calories, making it popular worldwide as a sugar substitute. However, it requires proper handling to maintain stability and has faced some controversy over potential health effects. Within established safe limits, aspartame offers a versatile, sweet addition to foods and beverages.