Category Chemistry

Calculate the enthalpy change for the reaction

1) Calculate the enthalpy change for the reaction: P4O6(s)+2O2(g)>>P4O10(s) given the following enthalpies of reaction: P4(s)+3O2(g)>>P4O6(s) deltaH = -1640.1 kJ P4(s)+5O2(g)>>P4O10(s) deltaH = -2940.1 kJ 2) From the enthalpies of reaction: H2(g)+F2(g)>>2HF(g) deltaH = -537kJ C(s)+2F2(g)>>CF4(g) deltaH = -680kJ 2C(s)+2H2(g)>>C2H4(g)…

Chemistry Equations

1- What mass of Cu(s) is electroplated by running 28.5A of current through a Cu 2+ (aq) solution for 4.00 h ?Express your answer to three significant figures and include the appropriate units. 2-How many minutes will it take to…

Rate of disappearance

For the hypothetical reaction A → B, calculate the average rate of disappearance of A if the initial concentration of A is 0.91 M and the concentration of A after 90 minutes is 0.11 M.  8.9 * 10^-3 M/min -8.9…

A soluble unknown has contaminated your sample

A soluble unknown has contaminated your sample. It absorbs the same wavelength as your analyte, Allura Red dye. How will this affect your results, and what type of error is introduced? The measured absorbance will always be lower, creating systematic…

Types of chromatography

1. If you wish to extract aqueous acetic acid into hexane, is it more effective to adjust the aqueous phase to pH 3 or pH 8? 2. A chromatogram with ideal Gaussian bands has tr = 17.5 min and w…

Explain why oxygen atoms are neutral

1. Explain why oxygen atoms are neutral. 2. Compare: an atom’s structure to a ladder. What parts of the ladder correspond to the energy levels of the atom? Identify one way a real ladder is not a good model for…