The empirical formula is N₂O₅.
The empirical formula is the <em>simplest whole-number ratio of atoms</em> in a compound.
The ratio of atoms is the same as the ratio of moles, so our job is to calculate the <em>molar ratio of N:O</em>.
I like to summarize the calculations in a table.
<u>Element</u> <u>Moles</u> <u>Ratio¹ </u> <u> ×2² </u> <u>Integers</u>³
N 1.85 1 2 2
O 4.63 2.503 5.005 5
¹To get the molar ratio, you divide each number of moles by the smallest number (1.85).
²Multiply these values by a number (2) that makes the numbers in the ratio close to integers.
³Round off the number in the ratio to integers (2 and 5).
The empirical formula is N₂O₅.
Answer is 355 grams.
Explanation:
Given the molecular weights:
M
r
N
a
O
H
=
40
g
m
o
l
M
r
N
a
2
S
O
4
=
142
g
m
o
l
The analogy of the moles will be held constant:
n
N
a
O
H
n
N
a
2
S
O
4
=
2
1
n
N
a
O
H
n
N
a
2
S
O
4
=
2
For each one, substitute:
n
=
m
M
r
Therefore:
n
N
a
O
H
n
N
a
2
S
O
4
=
2
m
N
a
O
H
M
r
N
a
O
H
m
N
a
2
S
O
4
M
r
N
a
2
S
O
4
=
2
200
40
x
142
=
2
200
⋅
142
40
x
=
2
200
⋅
142
=
2
⋅
40
x
x
=
200
⋅
142
2
⋅
40
=
100
⋅
142
40
=
10
⋅
142
4
=
1420
4
=
=
710
2
=
355
g
r
a
m
s
(or just use a calculator)
answer= 0.5
explanation=
Carbon has a relative atomic mass of 12.
Oxygen has a relative atomic mass of 16.
12+(2x16)=44
Therefore 1 mole of CO2 has a relative atomic mass of 44.
22/44=0.5, so there is half a mole of CO2 in 22g of it
Answer:
B: Adding water, then adding solute
Explanation:
This is because, say you have a solution with a certain concentration.
If you add more water, it will become more diluted (less concentrated)
If you add more solute, it will become more concentrated.
Therefore if you add water and solute, it could cancel out, and the concentration would remain the same.
Hope this helps! Let me know if you have any questions/ would like anything further explained :)