Question

An unknown substance contains 35.5% C, 7.4% H, 46.9% O, and N. The molecular mass is 544g/mol. What is the chemical formula? Keep the order of elements in the same order they are listed in the question. An example of writing the formula would be C2H8.

Answer 1

To find the chemical formula of the unknown substance, convert the percentages to grams, then convert grams to moles using molar masses. Divide each mole value by the smallest mole value to get the simplest ratio. The resulting ratio gives the chemical formula. We get C2H5ON.

Step-by-step explanation:

To determine the chemical formula of the unknown substance, we need to find the ratio of each element in the compound. We can assume that we have 100g of the compound, so we can convert the percentages to grams. Then, we convert the grams of each element to moles using their molar masses. Finally, we divide each mole value by the smallest mole value to get the simplest ratio of elements in the compound. The resulting ratio gives us the chemical formula.

For example, if we assume we have 100g of the unknown substance, we have:

• 35.5g of C = 2.958 moles of C
• 7.4g of H = 7.343 moles of H
• 46.9g of O = 2.931 moles of O
• 58.2g of N = 4.049 moles of N

Dividing each mole value by 2.931 (the smallest mole value), we get approximately:

• 1 mole of C
• 2.5 moles of H
• 1 mole of O
• 1.38 moles of N

So, the simplest ratio is 1:2.5:1:1.38. Multiplying each ratio by a common factor (2 in this case) gives us the chemical formula C2H5ON. Therefore, the chemical formula of the unknown substance is C2H5ON.