Se le solicita que realice una evaluación de cromo en agua potable. Para esto, usted toma una muestra de 300 mL de agua y a partir de ésta prepara una serie de tres diluciones 1/2. Tomando en cuenta que el límite de concentración de cromo permitido en el agua potable es de 0.05 ppm y que la concentración detectada en la última dilución fue de 1.875×10−2 μg/mL. a) El valor de concentración del agua es... ppm

Agas mixture with a total pressure of 745 mmhg contains each of the following gases at the indicated partial pressures: co2, 245 mmhg ; ar, 119 mmhg ; and o2, 163 mmhg . the mixture also contains helium gas. part a what is the partial pressure of the helium gas? phe p h e = nothing mmhg request answer part b what mass of helium gas is present in a 10.2-l sample of this mixture at 283 k ? m m = nothing g request answer

Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change

In science class richard learns that a substance has a boiling point of 230 fahrenheit his teacher ask him to convert this temperature to degrees celsius what is the boiling point of his substance in degrees celsius