Every cell is surrounded by a thin membrane. What is the main function of this cell membrane?

Which part (s) of a telephone involves the conversion of sound waves to electrical signals? a) the microphone b) neither the speaker nor the microphone c) the speaker d) both the speaker and the microphone

What is 6421 in scientific notation

Chemist have developed a method of measuring the mass of an atom called what?

Radioactive decay can involve electrons.

What mass of water is produced from the complete combustion of 7.10*10-3 g of methane? Express your answer with the appropriate units.

Identify the spectator ions in the following complete ionic equation. 2k (aq) s2 - (aq) pb2 (aq) 2no-3 (aq) →pbs (s) 2k (aq) 2no-3 (aq) express your answers as ions separated by a comma.

4. A bird left its post and flew in a triangular path. It flew 21 yards south, 72 yards east and 75 yards diagonally to end back at the post. Is it a right triangle?

Condension occurs in the inside of your windows in Winters, why?

How can you use Hess's law to determine a reaction's enthalpy?

7. How much energy in KJ is released when 15.0 g of steam at 100.0 degrees Celsius is condensed and then frozen to ice at 0.0 degrees Celsius?