Which of the following substances has polar covalent bonds?
a
caf2

b
kbr

c
nh3

d
ch4

Water (2510 g ) is heated until it just begins to boil. if the water absorbs 5.09×105 j of heat in the process, what was the initial temperature of the water?

A5.000 g sample of niso4 h2o decomposed to give 2.755 g of anhydrous niso4. what is the formula of the hydrate? what is the full chemical name for the hydrate? what is the molar mass of the hydrate? niso4•_h2o what is the mass % of water in the hydrate?

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?