How Accurate Are My Molarity Calculations for Chemical Solutions?

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  • #1
AngelShare
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I was given several equations to use for this assignment so, before assuming that I got this right, I wanted to check my answers. I don't think I have them done correctly...:redface:

What is the molarity of a solution of silver perchlorate, AgClO4, if 3.2 moles of silver perchlorate are dissolved in 1.5 liters of water?

molarity = moles/ volume
molarity = 3.2/1.5
molarity = 2.13

How many moles of potassium iodide, KI, must be used to make 1.500 L of a 0.2 M solution?

moles = 1.500/0.2
moles = 7.5

What is the molarity of the solution produced when 151 g of sodium chloride, NaCl, is dissolved in enough water to prepare .375 L of solution?

molarity = grams/molar mass
molarity = 151/.375
molarity = 402.6

How many grams of potassium chloride, KCl, are needed to prepare 0.630 L of a 2.50 M solution of potassium chloride?

(2.50)(.630) = x/74.6
1.575= 74.6x
.021 = x
.021 grams
 
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  • #2
**Disclaimer**
I've learned from the past that I need to warn you ahead of time that I may be incorrect. I hope I don't accidentally mislead you.

What is the molarity of a solution of silver perchlorate, AgClO4, if 3.2 moles of silver perchlorate are dissolved in 1.5 liters of water?

Your work is correct, but make sure you check your significant figures.

How many moles of potassium iodide, KI, must be used to make 1.500 L of a 0.2 M solution?

M = mol / L ; mol = L * M

What is the molarity of the solution produced when 151 g of sodium chloride, NaCl, is dissolved in enough water to prepare .375 L of solution?

M = mol / L ; M = (g / molecular mass) / L

In other words, convert grams to moles first, and then plug that into the original equation.

How many grams of potassium chloride, KCl, are needed to prepare 0.630 L of a 2.50 M solution of potassium chloride?

You started it off right, but you finished it incorrectly. Think about it - you have moles, and you need to convert to grams. Using dimensional analysis, you would have to do:

mol ( g / mol) so that moles cancel leaving you with grams. So, what do you think you should do?
 
  • #3
ksinclair13 said:
**Disclaimer**
I've learned from the past that I need to warn you ahead of time that I may be incorrect. I hope I don't accidentally mislead you.
You have not (mislead).
 
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  • #4
kinsclair13 gave good explanations, for the third question you'll need to convert to moles, since molarity is moles/liter. The last one seems correct though, you'll need to find the moles, than simply convert from moles to grams using factor labeling.
 
  • #5
Actually, the only problem with the last one is an error in algebra. Double-check the math.
 
  • #6
Alright, let's see if I got this now... ^_^

1. 2.1...molarity? Is that how you put it?
2. .3 moles
3. 6.88 molarity
4. 117.4 grams
 
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  • #7
Gokul43201 said:
Actually, the only problem with the last one is an error in algebra. Double-check the math.

Yeah, that was pretty stupid.:smile: I did it correctly on my paper the second time around and then, when I compared it to my first answer I thought, "How on Earth did I screw that up?"
 

FAQ: How Accurate Are My Molarity Calculations for Chemical Solutions?

What are moles of silver perchlorate?

Moles of silver perchlorate refer to the unit of measurement used to count the number of particles of silver perchlorate in a given sample. One mole of any substance contains 6.02 x 10^23 particles, which is known as Avogadro's number.

How is the number of moles of silver perchlorate determined?

The number of moles of silver perchlorate can be determined by dividing the mass of the sample in grams by the molar mass of silver perchlorate. The molar mass can be found by adding the atomic masses of each element in the compound, which for silver perchlorate is 207.22 g/mol for silver and 122.44 g/mol for perchlorate.

What is the significance of moles in chemistry?

Moles are an important unit of measurement in chemistry because they allow for easier comparison and calculation of the quantities of different substances. They also help in determining the ratios and proportions of elements in a compound, which is crucial in understanding chemical reactions.

How is the concept of moles related to the atomic theory?

The concept of moles is related to the atomic theory because it is based on the idea that matter is made up of tiny particles called atoms. The number of moles in a substance is directly proportional to the number of atoms present, making it an important concept in understanding the composition and behavior of matter.

Can moles of silver perchlorate be converted to other units of measurement?

Yes, moles of silver perchlorate can be converted to other units of measurement such as mass, volume, or number of particles. This can be done by using conversion factors and the molar mass of the compound.

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