compounds ionized by nitrogen and phosphorous containing compounds UV radiation sulfur or nitrogen containing compounds hydrocarbons Answer Bank thermionic electrolytic conductivity flame ionization halogenated compounds thermal conductivity photoionization mass spectrometer electron capture

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A sample containing an unknown quantity of cadmium in a water sample gave a reading of 1.4 in an atomic spectrometer. The sample was spiked with a 2 ppm mercury standard and gave a reading of 2.5. The instrument give a reading of zero with no sample. What is the concentration of cadmium in the unknown sample?

Titration of an oxalate sample gave the following percentages: 15.07 % , 15.58 % , and 15.42 % . Calculate the average. Calculate the standard deviation.

Use a chemical dictionary, chemical text or encyclopedia to find a specific definition of "chromatography." List a few mobile and stationary phases.

1.  All chromatography involves a solid phase, and mobile phase.  In thin layer chromatography the solid phase is the silica layer on a piece of glass, and the mobile phase is the organic solvent that will travel along the TLC plate. which direction will the mobile phase (the organic solvent) travel?  A) UPWARD B) DOWNWARD C) HORIZONTALLY LEFT TO RIGHT

You have obtained a gas chromatogram of a two component mixture of compounds A and B. The height of peak A is 3.84 cm. and the width at half height is 1 cm. The height of peak B is 3.49 cm. and the width at half height is 1.36 cm. The percentage of a component in the mixture is proportional to peak area. Estimate peak areas by multiplying height by width at half height. What was the percentage of compound B in the mixture? (Enter your answer as a number without any percent symbol or the word percent.)

Please choose an appropriate technique(s) to separate following compounds (it can be one, more than one, on none): Compound Melting Point Density Boiling Point Molar mass Phenol 40.5°C 1.07 g/cm 181.7°C 94.113 g/mol Toluene -95 °C 0.87 g/mL 111 °C 92.141 g/mol Simple Filtration Column Chromatography Distilation Crystallization/Re-Crystallization Separatory funnel None www. MacBook Air

Which statement(s) are correct for gas chromatography? A) the components in a mixture can be identified from their retention time. B) the relative peak areas give the proportions of components in a mixture. C) Calibration curves are used to confirms the concentrations of components in a mixture.

Which is correct?     Random errors affect accuracy and systematic errors affect precision.     An accurate result shows agreement with the true or accepted value.     Precise results can contain significant random error, but little systematic error.     The standard deviation is a good measure of accuracy.   Polydimethylsiloxane (PDMS) stationary phases have low polarities.  Which of the following statements is TRUE about gas chromatography using PDMS stationary phases?     The gas chromatography column is typically packed with silica microparticles.     An oven is used to control the column temperature because a constant temperature is always needed in gas chromatography     Octane (C8H18, boiling point: 126 ºC) is eluted later than dodecane (C12H26, boiling point: 216 ºC)     3-Pentanone ((C2H5)2CO, boiling point: 102 ºC) is eluted later than propanol (CH3CH2CH2OH, boiling point: 97 ºC)