Select all the correct answers. Based on the enthalpy changes given for the reactions, which reactions are endothermic?

2H2O → 2H2 + O2, ΔH = 484 kJ
C + O2 → CO2, ΔH = -394 kJ
H2 + Br2 → 2HBr, ΔH = -73 kJ
2NH3 → N2 + 3H2, ΔH = 92 kJ

Which best explains why an iceberg floats?

To find the work done, the force exerted and distance moved are multiplied. a couch is moved twice before you are happy with its placement. the same force was used to move the couch both times. if more work is done the first time it is moved, what do you know about the distance it was moved? a) when more work was done, the couch was moved the same distance. b) when more work was done, the couch was moved less. c) when more work was done, the couch was moved further. d) when more work was done, the couch wasn't moved at all.

What type of chemical bond is formed between two atoms of bromine 1. metallic 2. hydrogen 3. ionic 4. covalent