Is anyone good at 10th grade chemistry if so can someone help me please ? If I have 5 moles of a gas at a pressure of 6.5 atm and a volume of 14 liters, what is the temperature?

PV=nRT

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.