solving for pH

I have .20M of a solution NaCN. Ka for HCN = 4.0 x10 10. How do I solve for pH?

molarity and equilibrium

A sodium hydroxide solution was standardized by weighing 2.425 g of oxalic acid, H2C2O4*2H2o and diluting it to 250 mL in a volumetric flask. Then 25.0 mL of this acid solution was titrated with 30.20 mL of base. Based on this information, how do I calculate the molarity of the sodium hydroxide solution?

Wavelength

Suppose you are standing 225 m from a radio transmitter. What is your distance from the transmitter in terms of the number of wavelengths if a) The station is broadcasting at 1150kHz (on the Am radio band) (1 kHz=1 x 10^3(to the third power), or 1000 cycles per second) Distance from transmitter:___________________wavelength b) The station is broadcasting at 98.1 MHz (on the FM radio band) (1 MHz=10^6 (to the sixth power Hz, or 1 million cycles per second) Distance from transmitter:___________wavelengths

Wavelength

Violet light has a wavelength of about 410 nm. What is its frequency? Calculate the energy of one photon of violet light. What is the energy of 1.0 mol of violet light photons? Compare the energy of photons of violet light with those of red light. Which is more energetic and by what factor? Frequency of violet light:___________ Energy of one photon:______________ Energy of 1.0 mol of violet photons:_____________ Compare the energy of photons of violet light with those of red light. Which is more energetic and by what factor? ______________________

Wavelength

If OTA 104289 is available please assist. If not, please list step by step. Thank You. A beam of electrons (m=9.11 x 10 (-31) negative thirty first power has an average speed of 1.3 x 10^8 (eigth power) m*s (-1) s to to the negative first power. What is the wavelength of electrons having this average speed? ^=____________________________m Assums your eyes receive a signal crossing of blue light, ^=470nm. The energy of the signal is 2.50 x 10 ^14 (negative 14) J. How many photons reach your eyes?