QUICKKK

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 %

mass % H2O = (355 grams / 355.21 grams) *100%

mass % H2O = 99.941 %

8 0

3 years ago

How many moles of PC15 can be produced from 58.0 g of Cl₂ (and excess<br> P4)?

ludmilkaskok [199]

0.3268 moles of PC15 can be produced from 58.0 g of Cl₂ (and excess

P4)

<h3>How to calculate moles?</h3>

The balanced chemical equation is

$P_{4} + 10Cl_{2} = 4PCl_{5}$

The mass of clorine is m( $Cl_{2}$ ) = 58.0 g

The amount of clorine is n( $Cl_{2}$ ) = m( $Cl_{2}$ )/M( $Cl_{2}$ ) = 58/70.906 = 0.817 mol

The stoichiometric reaction,shows that

10 moles of $Cl_{2}$ yield 4 moles of $PCl_{5}$ ;

0.817 of $Cl_{2}$ yield x moles of $PCl_{5}$

n( $PCl_{5}$ ) = 4*0.817/10 = 0.3268 mol

To know more about stoichiometric reaction, refer:

brainly.com/question/14935523

#SPJ9

3 0

1 year ago

Which part of a chemical formula indicates the number of copies of molecules or compounds? A. plus signs B. subscripts C. coeffi

nadya68 [22]

I think it is C. coefficients but I don't know what subscripts are

3 0

3 years ago

A 155.0 g piece of copper at 128 oC is dropped into 250.0 g of water at 17.9 oC. (The specific heat of copper is 0.385 J/goC.) C

Mamont248 [21]

Answer:

$T_{eq}=23.85^oC$

Explanation:

Hello,

In this case, as the copper's heat loss is gained by the water, the following energetic relationship is:

$\Delta H_{Cu}=-\Delta H_{H_2O}$

Therefore the equilibrium temperature shows up as:

$m_{Cu}Cp_{Cu}(T_{Cu}-T{eq}) = m_{H_2O}Cp_{H_2O}(T_{eq}-T_{H_2O})\\\\T_{eq}=\frac{m_{Cu}Cp_{Cu}T_{Cu}-m_{H_2O}Cp_{H_2O}T_{H_2O}}{m_{Cu}Cp_{Cu}-m_{H_2O}Cp_{H_2O}} \\$

Thus, by knowing that water's heat capacity is 4.18J/g°C, one obtains:

$T_{eq}=\frac{155.0g*0.385\frac{J}{g^oC}*128^oC+250.0g*4.18\frac{J}{g^oC}*17.9^oC}{155.0g*0.385\frac{J}{g^oC}+250.0g*4.18\frac{J}{g^oC}}=23.85^oC$

Best regards.

6 0

3 years ago

Read 2 more answers

Add groups to complete polyvinyl alcohol, formed by the polymerization of the following monomer. If a carbon atom contains only

e-lub [12.9K]

Answer:

The resulting structure is:

R-CH-CH2 (OH)-CH-CH2(OH)-CH-CH2(OH)-CH-...

Explanation:

It can be said that vinyl alcohol cannot be polymerized by addition polymerization, since a very unstable radical would be formed, which is not possible. Generally, it is formed by polymerization and subsequent hydrolysis of the vinyl polyacetate. According to the exercise, the structure that results with its four units can be seen that the hydroxyl groups are found in the methylene carbons

8 0

3 years ago