Suppose you want to find the reaction enthalpy, ΔHrxn for the reaction,    X2 + O2  –> 2XO         ΔHrxn = ???  kJ where X is an imaginary element, by adding some combination of the reactions below.  You are not going to actually add the enthalpies for these reactions, but rather determine the multiplier for each reaction that will make them add to the reaction above.  If you use a reactions as written enter a “1”; if you need twice a reaction then enter a “2”; if you need to reverse a reaction, enter “-1”.  If you do not use a reaction, enter a “0”, etc. The only accepted answers are “0,  1/2, -1/2, 1, -1, 2, or -2”. Enter one of these answers in each blank corresponding to each reaction in order. 1)  X2 + 2O2 –> 2XO2                       ΔH = 50 2)  2XO + O2 –>  2XO2                    ΔH = -100 3)  XO2  + X2   –>  X2O + XO         ΔH = -50

A system composed of gases is compressed using 100. J of work while the system absorbs 450 J of heat.  What is the change in internal energy of this system in Joules?

If you have the value for the energy of a photon, which formula will give the wavelength of that photon?

 What is ∆T water in ⁰C ?

True or False:  X-rays travel faster than microwaves

Suppose I have samples of iron (.46 J/g K) and aluminum (.90 J/g K)   in an ice bath , and they have been there long enough that they are the same temperature as the ice bath.  Both samples weigh 10 grams.  I quickly take out the samples from the ice bath and drop them into separate identical containers of water at room temperature.  Which metal will cool the water in their container the most?

Which of the following reactions has a work term that is closest to zero? Consider only PV work.   

Saccharomyces sp. are typically known as the common yeast infection.

In this same agar plate, the satellite colonies forming swarm-like growth are:

The two methods for observing microbial cultures are: