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2 years ago

A solution is made from ethanol, C2H5OH and water is 0.75 m. How many grams of ethanol are contained per 250. g of water?

Chemistry

1 answer:

kumpel [21]2 years ago

8 0

Answer:

$m_{solute}=8.6g$

Explanation:

Hello,

In this case, the unit of concentration is molality which is defined by:

$m=\frac{n_{solute}}{m_{solvent}}$

Whereas the mass of the solvent is measured in kilograms. In such a way, with the given data, we first compute the kilograms of water:

$m_{solvent}=250g*\frac{1kg}{1000g} =0.25kg$

Then, we solve for the moles of the solute:

$n_{solute}=0.75\frac{mol}{kg}*0.25kg =0.19mol$

Finally since the molar mass of ethanol is 46 g/mol, we compute the grams for the given solution:

$m_{solute}=0.19*\frac{46g}{1mol} \\\\m_{solute}=8.6g$

Best regards.

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Answer:

Their amount is not consistent at all parts of the atmosphere

Explanation:

Carbon dioxide and water vapor exists as variable gases in the atmosphere because their amount varies from one part to the other.

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2 years ago

A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur.

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Answer:

Following are the responses to the given choices:

Explanation:

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2 years ago

I need some help with with question:

defon

Answer:

C1V1=C2V2

C1 is 2.0mol/l

V1=?

C2=.4mol/L

V2=100ml or for this 0.1L

V1 is 20ml

Best way to prepare this is to measure out 20ml of the 2 molar solution and add 80mL to it to get to 100mL

Explanation:

8 0

2 years ago

What are the mole fraction and the mass percent of a solution made by dissolving 0.21 g KBr in 0.355 L water? (d = 1.00 g/mL.) m

IRISSAK [1]

Answer:

Mol fraction H2O = 0.99991

Mol fraction KBr = 0.00009

mass % KBr = 0.059 %

mass % H2O = 99.941 %

Explanation:

Step 1: Data given

Mass of KBr = 0.21 grams

Molar mass KBr = 119 g/mol

Volume of water = 355 mL

Density of water = 1.00 g/mL

Molar mass water = 18.02 g/mol

Step 2: Calculate mass water

Mass water = 355 mL * 1g /mL

Mass water = 355 grams

Step 3: Calculate moles water

Moles water = mass water / molar mass water

Moles water = 355 grams / 18.02 g/mol

Moles water = 19.7 moles

Step 4: Calculate moles KBr

Moles KBr = 0.21 grams / 119 g/mol

Moles KBr = 0.00176 moles

Step 5: Calculate total moles

Total moles = 19.7 moles + 0.00176 moles

Total moles = 19.70176 moles

Step 6: Calculate mol fraction

Mol fraction H2O = 19.7 moles / 19.70176 moles

Mol fraction H2O = 0.99991

Step 7: Calculate mol fraction KBr

Mol fraction KBr = 0.00176 / 19.70176

Mol fraction KBr = 0.00009

Step 6: Calculate mass %

mass % KBR = (0.21 grams / (0.21 + 355) grams) *100%

mass % KBr = 0.059 %

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mass % H2O = 99.941 %

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3 years ago

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