15.0 grams of NH4Cl is added to 80.0 grams of water in a calorimeter cup. The temperature of the solution goes from an initial temp of 22.0 ºC to 17.5 ºC. What is the change in heat in kcal/mol? Be sure to include a + or - sign.

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