Answer:
The answer is: <u>Al2O3</u>
Explanation:
The data they give us is:
To find the empirical formula without knowing the grams of the compound, we find it per mole:
- 0.545 g Al * 1 mol Al / 27 g Al = 0.02 mol Al
- 0.485 g O * 1 mol O / 16 g O = 0.03 mol O
Then we must divide the results obtained by the lowest result, which in this case is 0.02:
- 0.02 mol Al / 0.02 = 1 Al
- 0.03 mol O / 0.02 = 1.5 O
Since both numbers have to give an integer, multiply by 2 until both remain integers:
Now the answer is given correctly:
Answer:
see explanation below
Explanation:
Question is incomplete, so in picture 1, you have a sample of this question with the missing data.
Now, in general terms, the absorbance of a substance can be calculated using the beer's law which is the following:
A = εlc
Where:
ε: molar absortivity
l: distance of the light in solution
c: concentration of solution
However, in this case, we have a plot line and a equation for this plot, so all we have to do is replace the given data into the equation and solve for x, which is the concentration.
the equation according to the plot is:
A = 15200c - 0.018
So solving for C for an absorbance of 0.25 is:
0.25 = 15200c - 0.018
0.25 + 0.018 = 15200c
0.268 = 15200c
c = 0.268/15200
c = 1.76x10⁻⁵ M
The answer is D. A compound
Answer:
1.44 x 10²⁵ ions of Na⁺
Explanation:
Given parameters:
Mass of NaCl = 1.4kg = 1400g
Unknown:
Number of ions of sodium = ?
Solution:
The compound NaCl in ionic form can be written as;
NaCl → Na⁺ + Cl⁻
In 1 mole of NaCl we have 1 mole of sodium ions
Now, let us find the number of moles in NaCl;
Number of moles =
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Number of moles =
= 23.93mol
So;
Since 1 mole of NaCl gives 1 mole of Na⁺
In 23.93 mole of NaCl will give 23.93 mole of Na⁺
1 mole of a substance = 6.02 x 10²³ ions of a substance
23.93 mole of a substance = 6.02 x 10²³ x 23.93
= 1.44 x 10²⁵ ions of Na⁺