Without doing any calculations, match the following thermodynamic properties with their appropriate numerical sign for the following exothermic reaction. 2C2H6(g) + 7O2(g) → 4CO2(g) 6H2O(g)

a. ΔHrxn > 0
b. ΔSrxn < 0
c. ΔGrxn = 0
d. ΔSuniverse > 0 low T, < 0 high T
< 0 low T, > 0 high T

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.

Calculate the estimated density of each ball. use the formula d = m/v where d is the density, m is the mass, and v is the volume. record your calculations in table a of your student guide. given that the density of water is 1.0 g/cm3, make a prediction about whether each ball will float in water. record your prediction in table a. what is the estimated density of the table tennis ball? record your answer to the nearest hundredth

Who discovered a pattern to the elements in 1869?