Chemicals used in cold packs do not produce ice, so why do they feel cold on your skin?

Which best describes why nh4+ can form an ionic bond with ci-?

Which statement best describes the relationship between period and frequency of light waves? a) in wave b the period increases and the frequency decreases from wave a. b) in wave a the period increases and the frequency decreases from wave b. c) in wave b the period is shorter and the frequency is greater than in wave a. d) in wave a the period is shorter and the frequency is greater than in wave b.

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?