Question

The properties of a mixture are typically averages of the properties of its components. The properties of a compound may differ dramatically from the properties of the elements that combine to produce the compound. For each process described below, state whether the material being discussed is most likely a mixture or a compound, and state whether the process is a chemical change or a physical change. a. An orange liquid is distilled, resulting in the collection of a yellow liquid and a red solid. b. A colorless, crystalline solid is decomposed, yielding a pale yellow-green gas and a soft, shiny metal. c. A cup of tea becomes sweeter as sugar is added to it.

Short answer

a. Mixture, Physical change b. Compound, Chemical change c. Mixture, Physical change

Step-by-step solution

a. Orange liquid is distilled

In this process, an orange liquid is distilled and we obtain a yellow liquid and a red solid. Distillation is a separation technique based on differences in the boiling points of components in a mixture. Since it is possible to separate the initial substance into different substances, the orange liquid is a mixture. Distillation is a physical change because it only affects the phase of the substances without changing their chemical composition. Answer: Mixture, Physical change

b. Colorless, crystalline solid is decomposed

This process involves the decomposition of a colorless, crystalline solid, yielding a pale yellow-green gas and a soft, shiny metal. Decomposition is a chemical change because it involves breaking of chemical bonds and formation of new substances. The initial substance is composed of more than one element chemically combined, so it is a compound. Answer: Compound, Chemical change

c. Sugar is added to a cup of tea

In this process, sugar is added to a cup of tea, making it sweeter. This is a process of creating a homogeneous mixture, where sugar dissolves in the liquid (tea) uniformly, but no new compound is formed. This is a physical change because only the physical properties of the tea (e.g., taste) are altered, while the chemical composition of both the tea and sugar remain unchanged. Answer: Mixture, Physical change