I have six questions here that I have no idea how to anser. If anybody can help me and explain them to me, I'd really really really appreciate it. Thanks alot

When ice floasts in water, a small part of it extends above the surface. Interestingly enough, the volume of ice that extends above the surface is equal to the volume of the...
a. vast number of open spaces in the hexagonal ice crystals
b. water the ice displaces
c. both of these
d. neither of these

2.When 100 J of heat is added to a system that performs 60 J of work, the thermal energy change of the system is...
a. 0j
b. 100j
c. 60j
d. 40j
e none of these

3. When work is done by a system and no heat added to it, the temperautre of the system...
a.increases
b. decreases
c. remains unchanged

4. A container of air is at atmospheric pressure and 27 degrees c. to double the pressure in the container, it should be heated to...

5. A piece of iron and a cup of waterboth have the same temperature. if they are heated so the thermal energy of each doubles,...
a.the water will have the higher temp.
b. the iron will have the higher temp
c. both will have the same temp.
d. not enough information

6. Which of the following contracts most when the temp. is decreases? equal volumes of
a. iron
b. wood
c. helium
d. water
e. none of the above