TEAS 7 science study guide free

Correct Answer: D

Rationale: The correct answer is D: Transition metals. Transition metals are known for their vibrant colors and are commonly used in fireworks due to their ability to emit specific colors of light. The diverse electronic configurations of transition metals allow them to produce a variety of hues, making them ideal for creating colorful displays in fireworks. Choice A, Noble gases, do not typically produce vibrant colors in fireworks as they are colorless and odorless gases. Choice B, Alkali metals, are not known for their colorful displays in fireworks. Choice C, Halogens, can produce colors in fireworks, but they are not as commonly used for their vibrant hues compared to transition metals.

Correct Answer: C

Rationale: Disinfecting and reusing sterile medical devices is not a recommended method for preventing healthcare-associated infections (HAIs). Reusing sterile medical devices can increase the risk of infections due to inadequate sterilization or potential damage to the devices during the reprocessing process. Proper sterilization and disposal of single-use medical devices are essential in preventing the transmission of infections in healthcare settings. A) Handwashing with soap and water is a crucial method for preventing HAIs as it helps to remove and reduce the number of pathogens on the hands of healthcare workers, preventing the spread of infections. B) Proper use of personal protective equipment (PPE) such as gloves, gowns, masks, and eye protection is important in preventing the transmission of infections between patients and healthcare workers. C) Disinfecting and reusing sterile medical devices is not a recommended practice as it can lead to the transmission of infections if the devices are not adequately sterilized. Using single-use sterile medical devices helps to ensure that each patient receives a sterile device, reducing the risk of infections.

Correct Answer: D

Rationale: The correct answer is D: Transition metals. Transition metals are known for their vibrant colors and are commonly used in fireworks due to their ability to emit specific colors of light. The diverse electronic configurations of transition metals allow them to produce a variety of hues, making them ideal for creating colorful displays in fireworks. Choice A, Noble gases, do not typically produce vibrant colors in fireworks as they are colorless and odorless gases. Choice B, Alkali metals, are not known for their colorful displays in fireworks. Choice C, Halogens, can produce colors in fireworks, but they are not as commonly used for their vibrant hues compared to transition metals.

Correct Answer: B

Rationale: Refraction is the phenomenon that describes the bending of light as it travels from one medium to another with differing densities. This bending occurs due to the change in speed of light as it moves from one medium to another, causing the light rays to change direction. Reflection refers to the bouncing back of light when it hits a surface, diffraction is the bending of light around obstacles, and dispersion is the separation of light into its different colors. Therefore, in the context of light moving through different media, refraction accurately describes the observed bending phenomenon.

Correct Answer: C

Rationale: Malleability is the property that allows a substance to be hammered or rolled into thin sheets without breaking. It is the opposite of brittleness. Ductility refers to the ability of a material to be drawn into thin wires, not hammered into shapes. Viscosity is the measure of a fluid's resistance to flow, indicating how thick or sticky it is, not related to shaping by hammering. Conductivity refers to the ability of a material to conduct electricity or heat, not resistance to being hammered into different shapes.