In which case is the work done on the system always positive?

An endothermic reaction has

Write the full electron configuration for Br: (Do not consider exceptions. Make sure to follow the order following the Aufbau principle, use the following format without superscripts: 1s2 2s2 2p6…)

A 91.9 MHz radio transmitter has a wavelength of [a] m and an energy of [b] J. Must show your work (scratch paper) to receive credit.  

Place the following types of electromagnetic radiation in order of increasingfrequency.             x-rays              radio waves              gamma rays

Use the standard enthalpies of formation provided to calculate the change in enthalpy for the reaction below: 2 Cl2(g)  +  2 H2O(l) → 4 HCl(g) + O2(g)            ΔH°f (kJ/mol) H2O(l)  -285.8 HCl(aq)  -167.2 HCl(g)  -92.3  Must show your work (scratch paper) to receive credit.

In which case is the work done on the system always positive?

When you look out the window at the blue sky you see light of a wavelenth of  473 nm. A photon of that light has a frequency of [a]Hz and an energy of [b] J. Must show your work (scratch paper) to receive credit.  

Light can be made to have a higher intensity by raising its

Write the full electron configuration for S: (Do not consider exceptions. Make sure to follow the order following the Aufbau principle, use the following format without superscripts: 1s2 2s2 2p6…)