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nataly862011 [7]
3 years ago
8

(a) Calculate the mass of CaCl2·6H2O needed to prepare 0.125 m CaCl2(aq) by using 500. g of water. (b) What mass of NiSO4·6H2O m

ust be dissolved in 500. g of water to produce 0.22 m NiSO4(aq)?
Chemistry
1 answer:
Alinara [238K]3 years ago
6 0

Answer:

(a) 13.7 g.

(b) 28.91 g.

Explanation:

  • molality (m) is the no. of moles of solute dissolved in 1.0 kg of solvent.

∴ m = (no. of moles of solute)/(mass of water (kg))

<em>∴ m = (mass/molar mass of solute)/(mass of water (kg)).</em>

<em />

<u><em>(a) Calculate the mass of CaCl₂·6H₂O needed to prepare 0.125 m CaCl₂(aq) by using 500. g of water.</em></u>

∵ m = (mass/molar mass of CaCl₂·6H₂O)/(mass of water (kg)).

m = 0.125 m, molar mass of CaCl₂·6H₂O = 219.0757 g/mol, mass of water = 500.0 g = 0.5 kg.

∴ 0.125 m = (mass of CaCl₂·6H₂O / 219.0757 g/mol)/(0.5 kg).

∴ mass of CaCl₂·6H₂O = (0.125 m)(219.0757 g/mol)(0.5 kg) = 13.7 g.

<u><em>(b) What mass of NiSO₄·6H₂O must be dissolved in 500. g of water to produce 0.22 m NiSO₄(aq)?</em></u>

∵ m = (mass/molar mass of NiSO₄·6H₂O)/(mass of water (kg)).

m = 0.22 m, molar mass of NiSO₄·6H₂O = 262.84 g/mol, mass of water = 500.0 g = 0.5 kg.

∴ 0.125 m = (mass of NiSO₄·6H₂O / 262.84 g/mol)/(0.5 kg).

∴ mass of NiSO₄·6H₂O = (0.22 m)(262.84 g/mol)(0.5 kg) = 28.91 g.

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Answer:

0.133 mL

Explanation:

Given data

  • Initial concentration (C₁): 15.0 M
  • Initial volume (V₁): to be determined
  • Final concentration (C₂): 0.001 M
  • Final volume (V₂): 2.00 L

We can find the volume of the concentrated solution using the dilution rule.

C₁ × V₁ = C₂ × V₂

V₁ = C₂ × V₂ / C₁

V₁ = 0.001 M × 2.00 L / 15.0 M

V₁ = 1.33 × 10⁻⁴ L = 0.133 mL

5 0
3 years ago
Calculate the percent error in calculating the pH of a 0.040 M HCl solution that is also 0.010 M in HNO3 using ionic strength an
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Answer:

O2+ e-→O2-εo’= -0.040 V+ 0.046 V= -0.925 Vb. Q = 1/0.02 = 50,the number of electrons transferred νe= 1, ε’=εo’-(0.0591V/νe)*logQ = -0.971V –0.0591V*log50 = -1.071 V

Explanation:

7 0
3 years ago
What is the mass of a 1.68-l sample of a liquid that has a density of 0.921g/ml?
Gwar [14]
Hey there!

Volume in mL :

1.68 L  * 1000 => 1680 mL

Density = 0.921 g/mL

Therefore:

Mass = density * Volume

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Explain the difference between biotic and abiotic
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7 0
3 years ago
Convert 4.5 X 1022 molecules of H2O to moles.
noname [10]

Answer:

<h3>The answer is 0.075 moles</h3>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

n =  \frac{N}{L}  \\

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

n =  \frac{4.5 \times  {10}^{22} }{6.02 \times  {10}^{23} }  \\  = 0.074750830...

We have the final answer as

<h3>0.075 moles</h3>

Hope this helps you

3 0
2 years ago
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