Why does an energy transfer not always result in phase change? Amplify question.

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

If we compare and contrast electromagnetic waves with sound waves, all but one statement is true. that is a) sound waves require a medium to travel while electromagnetic waves do not. b) electromagnetic waves can travel through the vacuum of space while sound waves cannot. c) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere. eliminate d) sound waves must bounce off of matter in order to travel while electromagnetic waves do not require matter to be present.

Based on the formulas, select the compounds below that are covalent: kbr sif4 al2o3 co2 naco3 s7o2 pcl3 fe3n2 h2o s2f10