When ammonium chloride is dissolved in water, the beaker gets cold. Which type of reaction does this describe?
exothermic
endothermic
both exothermic and endothermic
neither exothermic nor endothermic

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.

Given the data below for the reaction, 2 a + 2 b + 4 c => d + e + 3 f, the reaction is fill in the [ ] order in a, fill in the [ ] order in b, fill in the [ ] order in c and fill in the [ ] order overall. (use the words "first, second, third, fourth" to fill each blank)experimentinitial conc of a, mol/l initial conc of b, mol/l initial conc of c, mol/l initial rate, mol/l.s1 0.1 0.1 0.2 2 x 10-32 0.2 0.3 0.2 6 x 10-33 0.3 0.1 0.2 2 x 10-34 0.4 0.3 0.4 1.2 x 10-2

How is an endothermic reaction identified