Calcium Flouride. It's an ionic bond. Cation + anion with the suffix -ide
Answer:
Explanation:1.8
×
10
24
water molecules.
Explanation:
There are
6.022
×
10
23
molecules in a mole.
There are
18.01528
grams of water per mole of water.
These can be figured out using the concept of moles and molecular weight. I have attached a video that provides a good explanation.
Explanation of moles and molecular weight
Now you have all the information needed to solve the problem.
You start out with 54 grams of water. You want to convert that into molecules, but how can you do that? You can't go directly from grams to molecules because there is no easy unit conversion. However, you can go from grams to moles using
18.01528
grams of water per mole of water.
From there, you can go from moles to molecules using
6.022
×
10
23
molecules in a mole.
A T chart is useful for this kind of problem.
54 g H
2
O
×
1 mol H
2
O
18.0152 g H
2
O
×
6.022
×
10
23
molecules
1 mol H
2
O
54
g H
2
O
×
1 mol H
2
O
18.0152
g H
2
O
×
6.022
×
10
23
molecules
1 mol H
2
O
Notice when you apply this T chart, the units cancel out, leaving molecules in the final answer, which is the correct units.
Now actually multiply everything out
54
×
6.022
×
10
23
18.0152
=
1.805
×
10
24
You are left with
1.8
×
10
24
water molecules (rounded to two sig figs).
1 mol of any substance is made of 6.022 x 10²³ units, these units could be atoms making up elements or molecules making up a compound.
In this case. 1 mol of Li is made of 6.022 x 10²³ atoms of Li
The molar mass of Li is 6.94 g/mol
Therefore mass of 1 mol of Li is 6.94 g
In 6.94 g of Li there are - 6.022 x 10²³ atoms
Then in 766.3 g of Li there are - 6.022 x 10²³ atoms / 6.94 g x 766.3 g = 665 x 10²³
There are 6.65 x 10^25 atoms of Li
Out of the choices given, the one that describes a substance whose atoms all have the same number of protons are an element. The correct answer will be B.
Answer:
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