What is the pH to 2 decimal places after 21 mL of 0.20 M HCl is added to 125 mL of buffer prepared by mixing 0.10 M NH3 and 0.10 M NH4?

A100-watt light bulb radiates energy at a rate of 100 j/s. (the watt, a unit of power or energy over time, is defined as 1 j/s.) if all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second?

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3

What is a metal replacement reaction