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3 years ago

3) Calculate the percent by mass of 3.55 g NaCl dissolved in 88 g water.

Chemistry

1 answer:

kotykmax [81]3 years ago

5 0

Answer:

The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%

Explanation:

When a solute dissolves in a solvent, the mass of the resulting solution is a sum of the mass of the solute and the solvent.

A percentage is a way of expressing a quantity as a fraction of 100. In this case, the percentage by mass of a solution is the number of grams of solute per 100 grams of solution and can be represented mathematically as:

$Percent by mass=\frac{mass of solute}{mass of solution} *100$

In this way it allows to precisely establish the concentration of solutions and express them in terms of percentages.

In this case:

mass of solute: 3.55 g
mass of solution: 3.55 g + 88 g= 91.55 g

Replacing:

$Percentbymass=\frac{3.55}{91.55}*100$

Percent by mass= 3.88%

The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%

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Answer: The mass of PVB required to produce 1000 grams of tape is 213.4 grams

Explanation:

To calculate the mass of aluminium oxide, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$ .......(1)

For $Al_2O_3$

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50% (v/v) of $Al_2O_3$

This means that 50 mL of aluminium oxide is present in 100 mL of tape

Calculating the mass of aluminium oxide by using equation 1:

Density of aluminium oxide = $3.98 g/cm^3$

Volume of aluminium oxide = $50mL=50cm^3$ (Conversion factor: $1mL=1cm^3$ )

Putting values in equation 1, we get:

$3.98g/cm^3=\frac{\text{Mass of aluminium oxide}}{50cm^3}\\\\\text{Mass of aluminium oxide}=(3.98g/cm^3\times 50cm^3)=199g$

Mass of aluminium oxide = 199 g

For PVB:

We are given:

50% (v/v) of PVB

This means that 50 mL of PVB is present in 100 mL of tape

Calculating the mass of PVB by using equation 1:

Density of PVB = $1.08 g/cm^3$

Volume of PVB = $50mL=50cm^3$

Putting values in equation 1, we get:

$1.08g/cm^3=\frac{\text{Mass of PVB}}{50cm^3}\\\\\text{Mass of PVB}=(1.08g/cm^3\times 50cm^3)=54g$

Mass of PVB = 54 g

Mass of tape = Mass of aluminium oxide + mass of PVB

Mass of tape = [199 + 54] g = 253 g

To calculate the mass of PVB required to produce 1000 g of tape, we use unitary method:

When 253 grams of tape is made, the mass of PVB required is 54 g

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3 years ago

A sample of cacl2⋅2h2o/k2c2o4⋅h2o solid salt mixture is dissolved in ~150 ml de-ionized h2o. the oven dried precipitate has a ma

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We are given that the balanced chemical reaction is:

cacl2⋅2h2o(aq) + k2c2o4⋅h2o(aq) ---> cac2o4⋅h2o(s) + 2kcl(aq) + 2h2o(l)

We known that the product was oven dried, therefore the mass of 0.333 g pertains only to that of the substance cac2o4⋅h2o(s). So what we will do first is to convert this into moles by dividing the mass with the molar mass. The molar mass of cac2o4⋅h2o(s) is molar mass of cac2o4 plus the molar mass of h2o.

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Looking at the balanced chemical reaction, the ratio of cac2o4⋅h2o(s) and k2c2o4⋅h2o(aq) is 1:1, therefore:

moles k2c2o4⋅h2o(aq) = 2.28 x 10^-3 moles

Converting this to mass:

mass k2c2o4⋅h2o(aq) = 2.28 x 10^-3 moles (184.24 g /mol) = 0.419931006 g

Therefore:

The mass of k2c2o4⋅h2o(aq) in the salt mixture is about 0.420 g

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How is atomic number different from mass number?

Nimfa-mama [501]

Hello Gary My Man!

Well, as you can clearly see

The atomic number of an element is basically the number of protons it has. So yes, for every element this is different. Now, the mass number of an element as known, is the number of protons+the number of neutrons. So theoretically as we can see, this number should be a whole number, but since there are different isotopes (atoms of the same element with different numbers of neutrons) of each element, most periodic tables take account of that, so they often include decimals as seen.

So in Short, ALL the atoms of a particular element have the SAME EXACT atomic number (number of protons of course). The atoms of different elements have very different numbers of protons. And of course, the MASS number of an atom is the TOTAL number as known, of protons and of course, the neutrons it contains in it.

I Hope my answer has come to your Help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead! :)

(Ps. Mark As Brainliest IF Helped!)

-TheOneAboveAll :D

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