Chemistry Answers

Under constant pressure condition, a sample of hydrogen initially at 75 degree celcius and 6.2 L is cooled until its final volume is 5.4 L. What is it final temperature?

A sample of gas has a volume of 85.8 mL at 35 degrees. what volume will the sample occupy at 0 degrees when the pressure is held constant?

calculate the vapour pressure of solution at 25°C containing 26.9g of urea CO(NH2)2 in 712g H2O.( Vapour pressure of water at 25°C is 23.8mmHg)

When 0.600 liters Ar at 1.20 atm and 227°c is mixed with 0.200 liters of oxygen, at 591 torr and 127°c in a 400ml flask at 27°c, what is the pressure in the flask?

What is the percent by volume of ethanol in a solution that contains 45mL of ethanol dissolved in 125mL of water?

2. If a sample of helium gas has a volume of 120 mL and a pressure of 850 mm Hg, what is the new

volume if the pressure is changed to 425 mm Hg ?

How many milliliters of a 6.75 M NaOH solution would be needed to prepare 575 mL of a 3.01 M solution?

For a certain process at 127°C, ΔG = -16.20 kJ and ΔH = -17.0 kJ. What is the entropy change for this process at this temperature? Express your answer in the form, ΔS = ____________________ J/K.

Calculate ΔG⁰ at 298 K for the reaction below.

Fe₂O₃(s) + 13CO(g) > 2Fe(CO)₅(g) + 3CO₂(g)

ΔH⁰_f (kJ/mol) -824.2 -110.5 -733.8 -393.5

S⁰ (J/mol•K) 87.4 197.6 445.2 213.6

Calculate the ΔG⁰_f at 298 K for the PbCI₂(s) from the following information. ΔG⁰ for the reactions below is -58.4 kJ at 298 K.

PbS(s) + 2HCI(g) > PbCI₂(s) + H₂S(g)

ΔG⁰_f (kJ/mol) 97.82 149.0 0 -228.6