Well the answer to number 1 is definitely B
number 2 is B
number 3 is D
Number 4 is C
Hope this helps:)
We subtract the enthalpies of the reactants from that of the products:

Since this is < 0, this is an exothermic reaction.
Answer:
D, if the cliff is higher than the refrigerator
Explanation:
Gases, unlike solids and liquids, have neither fixed volume nor shape. They are molded entirely by the container in which they are held.
Answer:
will be 90054 J
Explanation:
Number of moles = (mass)/(molar mass)
Molar mass of
= 134.45 g/mol
So, 1.00 g of
=
of
= 0.00744 mol of 
0.00744 mol of
produces 670 J of heat
So, 1 mol of
produces
of heat or 90054 J of heat