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3 years ago

Qué concentración en % m/m tendrá una solución preparada con 20 g de NaCl (cloruro de sodio, sal común) y 200 g de agua?

Chemistry

1 answer:

alexgriva [62]3 years ago

4 0

Answer:

$\%m/m = 10\,\%$

Explanation:

El porcentaje masa a masa de la solución se obtiene al dividir la masa del cloruro de sodio por la masa del agua (The mass-mass percentage of solution is obtained by dividing the mass of sodium chloride by the mass of water):

$\%m/m = \frac{20\,g}{200\,g}\times 100\,\%$

$\%m/m = 10\,\%$

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2 Na + Cl ---> 2NaCl

Greeley [361]

Answer:

1. d. 84g

2. c. 77.4%

Explanation:

1. Based on the reaction 2 moles of Na produce 2 moles of NaCl.

The moles of Na (22.99g/mol) in 33g are:

33g * (1mol / 22.99g) = 1.435 moles Na = 1.435 moles NaCl must be produced.

The mass of NaCl is (Molar mass: 58.44g/mol):

1.435moles * (58.44g / mol) = 84g

d. 84g

2. Percent yield is defined as 100 times the ratio between actual yield (65g) and theoretical yield (84g). The percent yield is:

65g / 84g * 100 =

c. 77.4%

5 0

3 years ago

2Na2O2 + 2CO2 → 2Na2CO3 + O2

ahrayia [7]

the actual yield is the amount of Na₂CO₃ formed after carrying out the experiment

theoretical yield is the amount of Na₂CO₃ that is expected to be formed from the calculations

we need to first find the theoretical yield

2Na₂O₂ + 2CO₂ ---> 2Na₂CO₃ + O₂

molar ratio of Na₂O₂ to Na₂CO₃ is 2:2

number of Na₂O₂ moles reacted is equal to the number of Na₂CO₃ moles formed

number of Na₂O₂ moles reacted is - 7.80 g / 78 g/mol = 0.10 mol

therefore number of Na₂CO₃ moles formed is - 0.10 mol

mass of Na₂CO₃ expected to be formed is - 0.10 mol x 106 g/mol = 10.6 g

therefore theoretical yield is 10.6 g

percent yield = actual yield / theoretical yield x 100%

81.0 % = actual yield / 10.6 g x 100 %

actual yield = 10.6 x 0.81

actual yield = 8.59 g

therefore actual yield is 8.59 g

7 0

3 years ago

Read 2 more answers

What are the substances making up a mixture called

dimulka [17.4K]

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A mixture can be regarded as physical combination involving two or more substances whereby each entities identities are retained, then mixed in the form such as ;