What is the standard enthalpy of formation of liquid methylamine (CH3NH2) ?C(s)+O2(g) -> CO2(g); ?H=-393.5 kJ 2H2O(l) -> 2H2(g)+O2(g); ?H=571.6 kJ N2(g)+O2(g) -> NO2(g); ?H=33.10 kJ 4CH3NH2(l)+13O2(g) -> 4CO2(g)+4NO2(g)+10H2O(l); ?H=-4110.4 kJ The calculated answer is -47.3 kJ/mol. Show the work to confirm or deny the answer

Which of the following is true for the actual yield of a reaction? it is always calculated as a ratio. it is the yield from the excess reactant. it is the yield from the limiting reactant. it is always less than the theoretical yield.

Since the gas in your graduated cylinder is a mixture of butane and water vapor, you must determine the partial pressure of the butane, pbutane, alone. to do this, consult a reference and record the partial pressure of the water vapor, pwater, at the temperature you recorded. use the following formula to compute the partial pressure of the butane. pbutane = atmosphere - pwater use the following combined gas law formula and compute the volume that the butane sample will occupy at stp. (hint: convert both temperatures to kelvin.) pbutane x voriginal = pstandard x vfinal troom tstandard use the following ratio and proportion formula to determine the mass of butane needed to occupy a volume of 22.4 l at stp. grams of butane you used “x” grams of butane ml of butane corrected to stp = 22,400 ml compute the theoretical molar mass of butane based on its formula and the atomic masses on the periodic table. compare your experimental results from #3 to the theoretical value of #4, computing a percent error of your findings using this formula: % error = measured value - accepted value x 100 accepted value use the following ratio and proportion formula to determine the mass of butane needed to occupy a volume of 22.4 l at stp. need asap

Identify the electromagnets with poles that are reversed from the electromagnet shown above