Answer:
63.55
Explanation:
relative atomic mass=(mass of isotope1×relative abundance)+(mass of isotope 2×relative abundance)/100
r.a.m=(62.93×69.09)+(64.93×30.91)/100
=(4347.8337)+(2006.9863)/100
=6354.82/100
=63.55
The brownish rock is a sedimentry rock was formed when things like sand, mud, or pebbles get laid down in layers. Eventually the layers are lithified.
The grey rock is a metamorphic rock and was when other rocks are changed because of heat or pressure. Earth movements can cause rocks to be deeply buried or squeezed. As a result, the rocks are heated and put under great pressure. They do not melt, but the minerals they contain are changed chemically, forming metamorphic rocks.
The red dots rock is an igneous rock. Igneous rock forms when hot, molten rock crystallizes and solidifies.
Answer:
Approximately 6.81 × 10⁵ Pa.
Assumption: carbon dioxide behaves like an ideal gas.
Explanation:
Look up the relative atomic mass of carbon and oxygen on a modern periodic table:
Calculate the molar mass of carbon dioxide 
:
.
Find the number of moles of molecules in that 
sample of :
.
If carbon dioxide behaves like an ideal gas, it should satisfy the ideal gas equation when it is inside a container:
,
where
is the pressure inside the container.
is the volume of the container.
is the number of moles of particles (molecules, or atoms in case of noble gases) in the gas.
is the ideal gas constant. 
is the absolute temperature of the gas.
Rearrange the equation to find an expression for , the pressure inside the container.
.
Look up the ideal gas constant in the appropriate units.
.
Evaluate the expression for :
.
Apply dimensional analysis to verify the unit of pressure.
Well you know that you have to balance out the equation to 0. So if I is -1 and Ca is +2 you know that I had to equal to -2. So you can do that by having two of them. So Ca=+2 and I2=-2 so CaI2 would equal 0 meaning that would be the correct answer. Hope that I explained that correct :)
