Question

In the presence of sulfuric acid, one molecule of ethanol (C2H6O) can react to form one molecule each of water and another product. Using the law of conservation of mass, describe a technique a chemist could use to predict the formula of the unknown product; then use the technique you described to predict the formula of the unknown product.

Options:
A) Weigh the reactants and products to ensure mass conservation.
B) Observe the color change during the reaction to identify the product.
C) Analyze the temperature change during the reaction for clues.
D) Measure the pH of the solution to determine the product's formula.

Answer 1

The technique to predict the product of a chemical reaction using the law of conservation of mass is to weigh the reactants and products. In the dehydration of ethanol under sulfuric acid, the product is diethyl ether, along with the formation of water.

Step-by-step explanation:

The correct technique to predict the unknown product following the law of conservation of mass is option A) Weigh the reactants and products to ensure mass conservation. By doing so, we use the relative atomic masses to ensure that the mass of the reactants equals the mass of the products. A chemist can then write down all the species present and attempt to classify the reaction to predict the products.

In the case of ethanol (C2H6O) reacting under sulfuric acid, it is a dehydration reaction, which typically forms either an alkene or an ether. Given that two molecules of ethanol are reacting under concentrated sulfuric acid at 140 degrees Celsius, the reaction would lead to the formation of diethyl ether (C4H10O) and water (H2O). This can be surmised from the knowledge that under these conditions, the dehydration of ethanol predominantly forms ether rather than an alkene.