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3 years ago

What is the molality of a solution containing 19.5g HCl and 257g of H2O?

1 answer:

8 0

M= 2.06

molality is m = moles/kg

if you look at the periodic table the mass of HCl is 36.458 rounded to 36.5

divide the 19.5g by the mass (36.5) and you’ll get 0.53

next, you convert g to kg so you divide by 1,000. 257/1,000 = 0.257

you plug those two answers into the equation > m= 0.53 mol HCl/ 0.257kg H20

the answer will be 2.06 when you divide and there’s how you get the molality.

remember, HCl is the solute and H20 is the solvent.

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You perform a distillation to separate a mixture of propylbenzene and cyclohexane, and you obtain 2.9949 grams of cyclohexane (d

Romashka-Z-Leto [24]

Answer:

66.67%

Explanation:

From the given information:

mass of cyclohexane = 2.9949 grams

density of cyclohexane = 0.779 g/mL

Recall that:

Density = mass/volume

∴

Volume = mass/density

So, the volume of cyclohexane = 2.9949 g/ 0.779 g/mL

= 3.8445 mL

Also,

mass of propylbenzene = 1.6575 grams

density of propylbenzene = 0.862 g/mL

Volume of propylbenzene = 1.6575 g/ 0.862 g/mL

= 1.9229 mL

The volume % composition of cyclohexane from the mixture is:

$= (\dfrac{v_{cyclohexane}}{v_{cyclohexane}+v_{propylbenzene}})\times 100$

$= (\dfrac{3.8445}{3.8445+1.9229})\times 100$

$= (\dfrac{3.8445}{5.7674})\times 100$

= 66.67%

6 0

3 years ago

Uranium-238 decays to lead-206 with a half-life of 4.5 x 109 yr. Determine how much uranium-238 decays in milligrams (to three s

Mamont248 [21]

Answer:

2.15 mg of uranium-238 decays

Explanation:

For decay of radioactive nuclide-

$N=N_{0}.(\frac{1}{2})^{\frac{t}{t_{\frac{1}{2}}}}$

where N is amount of radioactive nuclide after t time, $N_{0}$ is initial amount of radioactive nuclide and $t_{\frac{1}{2}}$ is half life of radioactive nuclide

Here $N_{0}=4.60 mg$ , $t=4.1\times 10^{9}yr$ and $t_{\frac{1}{2}}=4.5\times 10^{9}yr$

So, $N=(4.60mg)\times (\frac{1}{2})^{\frac{4.1\times 10^{9}}{4.5\times 10^{9}}}$

so, N = 2.446 mg

mass of uranium-238 decays = (4.60-2.446) mg = 2.15 mg

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3 years ago

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Anarel [89]

Answer:

it states that the total mass of the products are the same as the total mass of the reactants in a chemical reaction.

Explanation:

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3 years ago

Please help on 44. /45./ 46./47,

Aleonysh [2.5K]

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4 years ago

What is the molarity of a solution in which 7.1 g of sodium sulfate is dissolved in enough water to make 100. mL of solution?

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Answer:

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Explanation:

Given data