CALORIMETRY PROBLEMS 1. Calculate the specific heat of a metal if 2.36 x 10 grams of it at 99.5°C is added to 125.0 mL of water at 22.0°C. The final temperature of the system is 25.4°C.

2. A lump of chromium (Cr) has a mass of 95.3 grams and a temperature of 90.5°C. It is placed into a calorimeter with
75.2 mL of water at 20.5°C. After stirring, the final temperature of the water, Cr metal, and calorimeter is 28.6°C. What is the specific heat of Cr metal?

3. A 100.0 gram sample of water at 50.0°C is mixed with a 50.00 gram sample of water at 20.0°C. What is the final temperature of the 150.0 grams of water?

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?