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3 years ago

What is the molarity of a solution of 14.0 g NH4Br in enough H2O to make 150 mL of solution?

2 answers:

8 0

The molarity of a solution equals to the mole number of the solute/the volume of the solution. For NH4Br, we know that the mole mass is 98. So the molarity is (14/98) mol /0.15 L=0.95 mol/L.

aniked [119]3 years ago

4 0

Explanation:

Molarity is defined as the number of moles per liter of solution.

Mathematically, Molarity = $\frac{no. of moles}{volume of solution in liter}$

Since it is given that the molarity of a solution of 14.0 g and volume is 150 mL or 0.15 L.

Whereas number of moles = $\frac{mass}{molar mass}$

So, molar mass of $NH_{4}Br$ is 97.94 g/mol.

Thus, number of moles = $\frac{14.0 g}{97.94 g/mol}$

= 0.142 mol

Therefore, calculate the molarity as follows.

Molarity = $\frac{no. of moles}{volume of solution in liter}$

= $\frac{0.142 mole}{0.15 L}$

= 0.946 mol/L

Hence, we can conclude that molarity of the solution is 0.946 mol/L.

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A permeation membrane separates an inlet air stream, F, (79 mol% N2, 21 mol% O2), into a permeate stream, M, and a reject stream

Norma-Jean [14]

Answer:

Permeate stream: M=10,47 L/min
Reject stream: J=38,24 L/min

Explanation:

Using the law of mass conservation, we have that the moles of any component in the inlet air stream equals the moles of this compenent in the two outlets stream. Being A the mole flowrate for the permeate stream and B the mole flowrate for the reject stream (both in mol/min), we have equation (1) and (2):

Oxygen:

2 mol/min * 0,21 = A mol/min * 0,50 + B mol/min * 0,13 ......................(1)

0,42 = 0,5A + 0,13B...........................(1)

Nitrogen:

2 mol/min * 0,79 = A mol/min * 0,50 + B mol/min * 0,87 ......................(2)

1,58 = 0,5A + 0,87B...........................(2)

Solving this system:

1,58 = 0,5A + 0,87B...........................(2)

0,42 = 0,5A + 0,13B...........................(1)

1,16 = 0A + 0,74B...............................(2) - (1)

1.16=0,74B

1,16/0,74=B

B=1,57 mol/min

And now replacing B in equation (1):

1,58 = 0,5A + 0,87*1,57

1,58-1,37=0,5A

0,21/0,5=A

A=0,43 mol/min

To calculate the volumetric flowrate of the permeate stream (M) and the reject stream (J), we just replace the given and calculate data into the ideal gas equation:

PV=nRT,.................... V = nRT/P

Permeate stream:

$M= \frac{0,43 \frac{mol}{min}*8,314\frac{m3Pa}{molK}*293K }{0,1 MPa*\frac{10^{6}Pa }{1 MPa} }=0,01047\frac{m^{3} }{min} * \frac{1000 L}{1 m^{3} }=10,47 L/min$

Rejct stream:

$J= \frac{1,57 \frac{mol}{min}*8,314\frac{m3Pa}{molK}*293K }{0,1 MPa*\frac{10^{6}Pa }{1 MPa} }=0,0382\frac{m^{3} }{min} * \frac{1000 L}{1 m^{3} }=38,24 L/min$

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At first, the energy in the diagram is the energy of the reactants.

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A decomposition reaction, with a rate that is observed to slow down as the reaction proceeds, has a half-life that does not depe

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