chem 100 - introduction to chemistry - fall 2025\nq15. (2 points) complete the following equation for the…

chem 100 - introduction to chemistry - fall 2025\nq15. (2 points) complete the following equation for the way ozone protects us from harmful uv light with λ < 320 nm: uv + ____(g) → o(g) + ____, reaction is endo- / exo- (circle one) thermic.\nq16. (1 point) true / false (circle one): photosynthesis is a reaction in many organisms using co₂ gas and water as reactants, driven by photon energy from sunlight.\nq17. (3 points) suggest three responses of the body to overexposure to outdoor sunlight: 1) 2) 3)\nq1. (1 point) an element having a lewis diagram of one dot - pair and 3 single dots is from group ____ of the periodic table.\n** end of practice quiz 7

chem 100 - introduction to chemistry - fall 2025\nq15. (2 points) complete the following equation for the way ozone protects us from harmful uv light with λ < 320 nm: uv + ____(g) → o(g) + ____, reaction is endo- / exo- (circle one) thermic.\nq16. (1 point) true / false (circle one): photosynthesis is a reaction in many organisms using co₂ gas and water as reactants, driven by photon energy from sunlight.\nq17. (3 points) suggest three responses of the body to overexposure to outdoor sunlight: 1) 2) 3)\nq1. (1 point) an element having a lewis diagram of one dot - pair and 3 single dots is from group ____ of the periodic table.\n** end of practice quiz 7

Answer

Explanation:

Q15:

The ozone - oxygen cycle involves the reaction of ozone ($O_3$) with UV light. The reaction is $UV+O_3(g)\rightarrow O(g) + O_2(g)$. This reaction is endothermic because energy (UV light) is absorbed to break the bonds in ozone.

Q16:

Photosynthesis is indeed a reaction in many organisms where carbon - dioxide ($CO_2$) and water ($H_2O$) are reactants, and the energy from sunlight (photon energy) drives the reaction to produce glucose and oxygen. So the statement is True.

Q17:

  1. Sunburn: Overexposure to UV rays can cause the skin to become red, painful, and inflamed.
  2. Tanning: The body produces more melanin as a defense mechanism against UV radiation, leading to a darker skin color.
  3. Premature aging: Long - term overexposure can lead to wrinkles, age spots, and loss of skin elasticity.

Q1:

The total number of valence electrons in the Lewis diagram is 7 (1 pair + 3 singles). Elements with 7 valence electrons are in Group 17 of the periodic table.

Answer:

Q15: $UV+O_3(g)\rightarrow O(g) + O_2(g)$, endo - thermic Q16: True Q17:

  1. Sunburn
  2. Tanning
  3. Premature aging Q1: 17