sapling hw #7

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alexandralopez 3F
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sapling hw #7

Postby alexandralopez 3F » Fri Oct 09, 2020 4:51 pm

Hi guys!

Im having trouble with #7 on the hw for this week: A solution of CaCl2 in water forms a mixture that is 32.5% calcium chloride by mass. If the total mass of the mixture is 590.1 g, what masses of CaCl2 and water were used?

Can someone explain how they approach a problem like this/what would their first step be

thanks!

Kaili Valenzuela 2B
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Re: sapling hw #7

Postby Kaili Valenzuela 2B » Fri Oct 09, 2020 5:02 pm

Hello!
So in order to find the mass of CaCl2 you are going to have to multiply the 36.5% of calcium chloride by the total mass of the mixture, 903.4 g:
mass CaCl2= 903.4g x 36.5% = 329.74 g CaCl2

Second, in order to find the mass of water used you are going to have to subtract the mass of CaCl2 from the total mass, 903.4g:
mass of H2O= 903.4g - 329.74g= 573.99 g of H2O

Hope this helps!

Audra Mcleod 3G
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Re: sapling hw #7

Postby Audra Mcleod 3G » Fri Oct 09, 2020 5:05 pm

Hello!
For this problem the solution is easier than you would think. To find the mass of calcium chloride you multiply .325 with 590.1 g (giving you about 191.78 g), as you know that calcium chloride would constitute 32.5% of the total mass of this mixture. Then to find the mass of the water, you would subtract the product you calculated earlier from the total mass of 590.1 g ( so 590.1 - 191.78 = about 398.32 g water).

Eliana Carney 3E
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Re: sapling hw #7

Postby Eliana Carney 3E » Fri Oct 09, 2020 5:35 pm

Hey! This problem is actually easier than you might think. I know I was overthinking it before I realized that it's just multiplication and subtraction.

The first thing you have to do is figure out the mass of calcium chloride. It is given than the mixture contains 32.5% calcium chloride, so all you do here is multiply the total mass of mixture (590.1 g) by 0.325. When you do this, you find that there is 191.8 g of calcium chloride.

Then you subtract the mass of calcium chloride (191.8 g) from the mass of the total mixture (590.1 g) to find the mass of water. When you do this, you find that there is 398.3 g of water.

Hope this helps!

Mehreen 3I
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Re: sapling hw #7

Postby Mehreen 3I » Fri Oct 09, 2020 6:28 pm

Hi! For this problem, it says that 32.0% of the mixture is calcium chloride and the total mass of the mixture is 310.1 g with the water. First, you have to find the amount of calcium chloride in the solution so you would multiply 310.1 g by .32 to get that the mass of CaCl2 is 99.2 g. The remainder of the solution would be the water so you would just subtract that value from the total mass. Therefore, 310.1 g -99.2 g = 210.9 g of water.

Daniel Hernandez 1G
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Re: sapling hw #7

Postby Daniel Hernandez 1G » Fri Oct 09, 2020 7:41 pm

Hello!

For this problem, it is a matter of converting the percentage of calcium chloride, 32.5%, into a decimal number, 0.325. Once you have this, you should be set to multiply the total mass by this number to determine the mass of calcium chloride. For the final step, you would have to use the given total mass and subtract the mass of calcium chloride to find the mass of water, the remaining difference.

Gicelle Rubin 1E
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Re: sapling hw #7

Postby Gicelle Rubin 1E » Sat Oct 10, 2020 2:54 pm

After reading some of the replies, I'm afraid I have a silly question.
People are saying to "multiply 0.325 with 590.1g" but my question is what they did to get 0.325 and why.
Thank you!

Aimee Alvarado 3J
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Re: sapling hw #7

Postby Aimee Alvarado 3J » Sat Oct 10, 2020 5:18 pm

Gicelle Rubin 1E wrote:After reading some of the replies, I'm afraid I have a silly question.
People are saying to "multiply 0.325 with 590.1g" but my question is what they did to get 0.325 and why.
Thank you!


They got .325 from the percentage of calcium chloride (32.5%). You would move the decimal point on the percentage two spots to the left, making it 0.325, and it just makes it easier to multiply the percentage with 590.1 g.

Marco Morales 2G
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Re: sapling hw #7

Postby Marco Morales 2G » Sun Oct 11, 2020 12:47 am

Gicelle Rubin 1E wrote:After reading some of the replies, I'm afraid I have a silly question.
People are saying to "multiply 0.325 with 590.1g" but my question is what they did to get 0.325 and why.
Thank you!


Don't be afraid! Because I too was wondering the same thing. Thank you for asking before I did! We're all in this together.

Thomas Gimeno
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Re: sapling hw #7

Postby Thomas Gimeno » Sun Oct 11, 2020 11:04 am

Well logically, if you add the mass of the CaCl2 and the water, you should get the mass of the total solution. And, CaCl2 represents 32.5% then the water must represent 67.5% because water+CaCl2=100%. So if you multiply the total mass by the .325 and .675 to find the masses of the CaCl2 and water respectivly.

Brandon McClelland3L
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Re: sapling hw #7

Postby Brandon McClelland3L » Sun Oct 11, 2020 12:57 pm

The mass of CaCl2 is going to be 32.5% of the total mass, so we just multiply the total mass by 0.325.

There are a couple ways you can do the next part of the problem, but the easiest is to subtract the mass of CaCl2 from the total mass, because we know that everything that isn't CaCl2 is water.

Nick P 3D
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Re: sapling hw #7

Postby Nick P 3D » Sun Oct 11, 2020 1:08 pm

The wording of this problem might make it seem more difficult than it really is, but when it comes down to it you just have to multiply. The only real conversion is taking the percentage and making that into a decimal, .325. Then, you are going to want to multiply this decimal by the total mass in order to find the amount that is calcium chloride. You can then just subtract the product from the total mass to find the remaining, which is all water.

Dylan_Nguyen_2C
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Re: sapling hw #7

Postby Dylan_Nguyen_2C » Sun Oct 11, 2020 3:16 pm

The way I looked at it is if the mixture is 32.5% calcium chloride by mass, then the other 67.5% of the solution must be water. We can multiply the total mass 590.1 by .675 to get the mass of the water in the solution. 590.1 x .675 = 398.3175 grams H2O

Danielle DIS2L
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Re: sapling hw #7

Postby Danielle DIS2L » Sun Oct 11, 2020 3:23 pm

Here is how I would solve it,

Since there is 32.5% of calcium chloride in the mixture, I would just multiply .325 with the total mixture which is 590.1 and I got 191.78g of CaCl2. I subtract 191.78g of CaCl2 from 590.1g of total mixture to get the grams of water used and I got 398.32g of water.

Abraham De Luna
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Re: sapling hw #7

Postby Abraham De Luna » Sun Oct 11, 2020 5:31 pm

Thanks guys, these explanations were very helpful.

Daniela Santana 2L
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Re: sapling hw #7

Postby Daniela Santana 2L » Sun Oct 11, 2020 10:34 pm

I approached this problem by imagining the calcium chloride in grams. So if your calcium chloride was 32.5% I thought of it as 32.5 g out of 100g. Then I set up two fractions with 32.5 over 100 equaling to x over the total mass of the mixture. I cross multiplied and 100x equaling the product of the total mass and the 32.5g. I then just solved for x by dividing. This is the mass of calcium chloride. To get the mass of water just subtract that number from the original total mass of the mixture.

Jacob Schwarz-Discussion 3I
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Re: sapling hw #7

Postby Jacob Schwarz-Discussion 3I » Sun Oct 11, 2020 10:40 pm

Hey!
For this problem, you know that 32.5% of the sln. is calcium chloride. Therefore, the other 67.5% of the sln. must be H20. If the sln. is 590.1g, then 32.5% of 590.1 is 191.78g of CaCl2. Then, after subtracting that mass from 590.1, you get the grams of H20 that make up the sln.

Jaclyn Schwartz 1I
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Re: sapling hw #7

Postby Jaclyn Schwartz 1I » Sun Oct 11, 2020 11:47 pm

This question is alot simpler than you think! To start you multiple the percent of CaCl by the total mass. That will you give you the grams of CaCl in the solution. Next just subtract the mass of the CaCl from the total mass of solution, which will give you the mass of the water. And thats it! hoped it helped


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