# Chem 2 test 3 flashcards

question

 A Sample of Helium gas at 745 torr and 45*C has a volume of of 80.0ml. What pressure is needed to Compress the volume of this sample at 35*C to half?

 P1= 45 Torr T1=    318 K V1=      .08 T2=    308K V2=      .04   1.44 x 10^3 torr
question

 Calculate the number of grams of ammonia in a gas sample at 765 torr and 32*C if the volume is 76.5 ml?

 n=PV     RT   .0522 g NH3
question

 Given the reaction Ca(OH)2 + 2HCL –> CaCl2 + 2H2O   Calculate the molarity of the HCL solution if a 0.435 gram sample of Ca(OH)2 required 26.8mL of acid to reach the end point.

 0.435g Ca(OH)2|1 mole Ca(OH)2|2mole HCL|.01174 74.08g|1mole CaCl2| 0.0268 L   3.15 x 10^-4m
question

 A gas has a molar mass of 48.0g/mole. Calculate the volume , in liters, of a sample weighing 3.67 grams, at STP

question

 How many grams of Sodium Chloride are needed to prepare 456 ml of a 10.2% solution?

 10.2g|456.ml 100ml   46.5 g
question

 How many milliliters of 14M sulfuric acid are needed to prepare 2.50 L of 0.340M solution?