At room temperature though which of the following substances would sound travel the slowest

Express the following number in scientific notation. 0.026890 =

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?

Answer asap need it by wednesday morning calculate the ph of 0.02m hcl best answer will be brainliest