8. A. Density is independent of size (an intensive property).
9. B. The highest density is 1786 g/20cm^3, or 89.3 g/cm^3. The least is 512 g/20cm^3, or 25.6 g/cm^3. Therefore, the difference is 89.3 - 25.6, or 63.7 g/cm^3.
10. C. A bottle filled with air weighs less than one filled with marshmallows, because air is less dense than marshmallows.
11. D. The number represents the number of protons in the nucleus of the atom, as well as the atomic number of the element.
12. C. The number represents the atomic mass of the element, which is determined based on the relative abundance of each form of the element.
Answer:
18.65004 grams H2O
Explanation:
First, we need to write down the balanced chemical equation for the decomposition reaction:
2LiOH -> H2O + Li2O
Since we have grams of LiOH and we need to know the grams of water, we need to convert to moles since we can only compare moles to moles.
The amu of LiOH is 23.947.
The given grams of LiOH is 63.. To convert to moles, we will divide 63 by 23.947..
This gives us 2.6310 moles LiOH..
To convert to moles of H2O (and later grams of H2O), we will use the mole fractions from the balanced equation...
When we look at the balanced equation we can see that 2 moles of LIOH can produce 1 mol of Water, so:
2.6310 moles
= 1.3155 moles H2O
Now we will convert from moles to grams (we must multiply by the amu)
1.3155 moles H2O = 18.65 grams H2O