How many moles of naf must be dissolved in 1.00 liter of a saturated solution of pbf2 at 25°c to reduce the [pb2+] to 1.0 × 10–6 m? the ksp for pbf2 at 25 °c is 4.0 × 10–8?

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?

One nanometer is equal to how many meters?