Which of the following is a characteristic of an S wave?

Why does his teacher ask him to balance the equation by including the correct coefficient

Match the mixture with the substance// i really need on this guys (it’s a pic btw)

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.