Which of the following statements is a hypothesis about the synthesis of gold nanoparticles? (LO 1.1) (a) Adding a salt solution to gold nanoparticles causes the color to change from red to blue. (b) To examine the effect of salt on gold nanoparticles, variable concentrations of salt are added to the nanopar-ticles and the results are measured (c) A solution of gold nanoparticles with an average diam-eter of 30 nm has a wavelength of maximum absorption of 450 nm and is a reddish-orange color. (d) Adding a substance with a negative charge to the surface of the nanoparticles creates repulsive forces that stabilize small particle size

Verified step by step guidance

1. Identify the statement that proposes a testable prediction or explanation about the synthesis of gold nanoparticles.
2. Evaluate each option to determine if it suggests a cause and effect relationship or a testable outcome related to the synthesis process.
3. Check if the statement (a) suggests a cause (adding a salt solution) and observes an effect (color change), which can be tested experimentally.
4. Assess statement (b) to see if it sets up an experimental condition (variable concentrations of salt) to observe specific outcomes on gold nanoparticles, which is characteristic of a hypothesis.
5. Review statements (c) and (d) to determine if they merely describe properties or effects without suggesting a testable prediction or explanation related to the synthesis of gold nanoparticles.

Key Concepts

Hypothesis Formation

A hypothesis is a testable statement that predicts the relationship between variables. It is often formulated based on observations and prior knowledge, serving as a foundation for experimentation. In scientific research, a good hypothesis should be specific, measurable, and falsifiable, allowing researchers to design experiments that can confirm or refute it.

Variables in Experiments

In scientific experiments, variables are elements that can change or be controlled. The independent variable is manipulated to observe its effect on the dependent variable, which is measured. Understanding the distinction between these variables is crucial for designing experiments and interpreting results, as it helps establish cause-and-effect relationships.

Nanoparticle Properties

Nanoparticles exhibit unique physical and chemical properties due to their small size and high surface area-to-volume ratio. These properties can include changes in color, stability, and reactivity, which are often influenced by their composition and the surrounding environment. In the context of gold nanoparticles, their optical properties, such as color changes, are particularly important for applications in sensing and imaging.