I need help asap please!! Calculate the change of enthalpy for the reaction CH4 (g) + NH3 (g) --> HCN (g) +3H2 (g) from the following reactions:

Reaction 1: N2 (g) + 3H2 (g) --> 2NH3 (g) Change in enthalpy: -91.8 kJ/mol

Reaction 2: C (s, graphite) + 2H2 (g) --> CH4 (g) Change in enthalply: -74.9 kJ/mol

Reaction 3: H2 (g) + 2C (s, graphite) + N2 (g) --> 2HCN (g) Change in enthalpy: +270.3 kJ/mol

Include the following:

The numerical answer with correct units.
State which reactions, if any, you had to "Flip".
State which reactions you had to multiply, if any, to get the correct amount of the compound. Also, include how much you multiplied the reaction by.

Identifying limitations of kinetic-molecular theorya chemist is studying the properties of a gas under various conditions. he observes that when the gas is at room temperature and low pressure, it behaves as an ideal gas. when the gas is cooled to 10 kelvin and is placed under high pressure, however, it deviates significantly from an ideal .

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

Define a is a tiny pavket of energy