Answer:
I cannot give you all the answer but I can help you to solve those.
Explanation:
The first question:
How many grams are there in 7.5×
molecules of 
?
So we need to find the molecular mass first, use your periodic table,
And then we can find out 2+32+16×4=98 g/mol
Then, we need to find how many moles, by using Avogadro's constant:
Avogadro's constant: 1 mole = 6.02×
∴
=1.25 mol(2d.p.)
Lastly, find the grams using the formula 
m=Mn
m=1.25*98
m=122.5g
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In conclusion, use those formula to help you:
(which M = molecular mass(atomic mass) m=mass of the substance and n = moles)
Avogadro's constant: 
Answer:
Antifreeze is whats used to keep your engine cool without freezing.
Explanation:
it keeps the engine from overheating.
It also prevents corrosion.
Here is a quote from google "Antifreeze works because the freezing and boiling points of liquids are “colligative” properties. This means they depend on the concentrations of “solutes,” or dissolved substances, in the solution. A pure solution freezes because the lower temperatures cause the molecules to slow down"
That quote is from "The Science Behind Antifreeze"
If you have any questions feel free to ask in the comments.
Answer:
Explanation:
Looking at the atom, you see that there is 1 carbon atom and 2 oxygen atoms.
The chemical formula of Carbon is just C (from the periodic table), and the chemical formula of Oxygen is just O (from the periodic table).
When you create the chemical formula of a compound, you want to indicate how many atoms of each element there are. Here, since there are 2 oxygen atoms, you want to have some form of 
, and since there's only 1 carbon atom, you want to have some form of C.
Now, we just put it together: (this is btw carbon dioxide)
Hope this helps!
