Answer:
the answer is A
I made a chart for AP chem if you want to refer to it.
If the absorbance of a KMnO4 solution of unknown concentration is 0.633, calculate the concentration of KMnO4 in the solution.
1 answer:
You might be interested in
Answer:
Explanation:
To convert from atoms to grams, you must first convert atoms to moles, then moles to grams.
1. Convert Atoms to Moles
To convert atoms to grams, Avogadro's number must be used.
This number tells us the number of particles (atoms, molecules, ions, etc.) in 1 mole. In this case, the particles are atoms of iodine.
Multiply the given number of atoms by Avogadro's number.
Flip the fraction so the atoms of iodine will cancel out.
Multiply so the problem condenses into 1 fraction.
2. Convert Moles to Grams
Now we must use the molar mass of iodine, which is found on the Periodic Table.
- Iodine Molar Mass: 126.9045 g/mol
Use this mass as a fraction.
Multiply this fraction by the number of moles found above.
Multiply. The moles of iodine will cancel.
The 1 as a denominator is insignificant.
3. Round
The original measurement of 1.76*10^23 has 3 significant figures (1, 7, and 6). Therefore we must round our answer to 3 sig figs. For this answer, that is the tenths place.
The 8 in the hundredth place tells us to round the 0 up to a 1.
There is about <u>37.1 grams of iodine </u>in 1.76*10^23 atoms.
Answer:
30 μmol/L
Explanation:
<em>A chemist prepares a solution of barium chloride by measuring out 8.9 μmol of barium chloride into a 300mL volumetric flask and filling the flask to the mark with water. </em>
<em> Calculate the concentration in μmol L of the chemist's barium chloride solution. Round your answer to 2 significant digits.</em>
<em />
The chemist has 8.9 μmol of solute (barium chloride) and he adds water until the mark of 300 mL in the container, which is the volume of the solution. We will need the conversion factor 1 L = 1000 mL. The concentration of barium chloride in μmol/L is: