What must be done to calculate the enthalpy of reaction? Check all that apply. The first equation must be halved. The first equation must be reversed. The second equation must be halved. The second equation must be reversed. The third equation must be halved. The third equation must be reversed. What is the overall enthalpy of reaction? Delta. Hrxn = kJ

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.