A) most gases become less soluble in water as the temperature increases. What ca

Question

A) most gases become less soluble in water as the temperature increases. What can be concluded about the signs of delta H soln and delta S soln in this case
1)) delta h soln is negative and delta s soln is negative 2)) delta h Soln is positive and delta s soln is negative 3))delta h soln is positive and delta s soln is positive 4)) delta h soln is negative and delta s soln is positive
B) Aques solutions of 30% by weight hydrogen peroxide h2o2 are used to oxidize metals or organic molecules in chemical reactions. Given the density of the solution is 1.11g/mL calculate molarity 1)6.78 2)9.78 3)0.794 d)12.6
C) the Henry's law constant of methyl bromide, CH3Br is k=.159 mol/(L*atm) at 25 C what is the solubility of it in water at 25 C at a partial pressure of 250 mm hg?
D) which of the following has the lowest freezing point? 1)0.035 m CH3CH2CH2OH 2)0.015 m MgCl2 3)0.0100 m NaCl 4)0.0100 m Li2SO4
E) a KCI solution is prepared by dissolving 40.0 g of KCl in 250.0 g of water at 25 what is the vapor pressure of the solution if the vapor pressure of water is 25 C is 23.76 mm hg 1)22.1 mm hg 2) 22.9 mm Hg 3) 25.5 mm Hg 3) 20.5 mm Hg
F) a solution of 62.4 g of insulin in enough water to make 1.000 l of solution has an osmotic pressure of .205 at 25 based on this what is the molar mass of insulin A) most gases become less soluble in water as the temperature increases. What can be concluded about the signs of delta H soln and delta S soln in this case
1)) delta h soln is negative and delta s soln is negative 2)) delta h Soln is positive and delta s soln is negative 3))delta h soln is positive and delta s soln is positive 4)) delta h soln is negative and delta s soln is positive
B) Aques solutions of 30% by weight hydrogen peroxide h2o2 are used to oxidize metals or organic molecules in chemical reactions. Given the density of the solution is 1.11g/mL calculate molarity 1)6.78 2)9.78 3)0.794 d)12.6
C) the Henry's law constant of methyl bromide, CH3Br is k=.159 mol/(L*atm) at 25 C what is the solubility of it in water at 25 C at a partial pressure of 250 mm hg?
D) which of the following has the lowest freezing point? 1)0.035 m CH3CH2CH2OH 2)0.015 m MgCl2 3)0.0100 m NaCl 4)0.0100 m Li2SO4
E) a KCI solution is prepared by dissolving 40.0 g of KCl in 250.0 g of water at 25 what is the vapor pressure of the solution if the vapor pressure of water is 25 C is 23.76 mm hg 1)22.1 mm hg 2) 22.9 mm Hg 3) 25.5 mm Hg 3) 20.5 mm Hg
F) a solution of 62.4 g of insulin in enough water to make 1.000 l of solution has an osmotic pressure of .205 at 25 based on this what is the molar mass of insulin
1)) delta h soln is negative and delta s soln is negative 2)) delta h Soln is positive and delta s soln is negative 3))delta h soln is positive and delta s soln is positive 4)) delta h soln is negative and delta s soln is positive
B) Aques solutions of 30% by weight hydrogen peroxide h2o2 are used to oxidize metals or organic molecules in chemical reactions. Given the density of the solution is 1.11g/mL calculate molarity 1)6.78 2)9.78 3)0.794 d)12.6
C) the Henry's law constant of methyl bromide, CH3Br is k=.159 mol/(L*atm) at 25 C what is the solubility of it in water at 25 C at a partial pressure of 250 mm hg?
D) which of the following has the lowest freezing point? 1)0.035 m CH3CH2CH2OH 2)0.015 m MgCl2 3)0.0100 m NaCl 4)0.0100 m Li2SO4
E) a KCI solution is prepared by dissolving 40.0 g of KCl in 250.0 g of water at 25 what is the vapor pressure of the solution if the vapor pressure of water is 25 C is 23.76 mm hg 1)22.1 mm hg 2) 22.9 mm Hg 3) 25.5 mm Hg 3) 20.5 mm Hg
F) a solution of 62.4 g of insulin in enough water to make 1.000 l of solution has an osmotic pressure of .205 at 25 based on this what is the molar mass of insulin

Explanation / Answer

A)

delta(H)<0 since the process is exothermic(from gas to aqueous) and also most gases have negative enthalpy change
delta(S)<0 since the gas is less soluble in water at high temperatures
delta(G)=delta(H)-T*delta(S)
delta(H)<0 and delta(S)<0 then less soluble at high temperature

option 1

B)

As deneity = mass / volume
mass = 1.11 * 1
= 1.11g of solution

As the solution is 30%
mass H2O2 = 1.11*30%
= 0.333g

Moles = mass / MW
= 0.333 / (2*1.01 + 2*16.0)
= 9.78*10^-3

conc = moles / vol (in litres)
= 9.78*10^-3 / 0.001
= 9.78M which is option 2

C)

D)

a) -0.015* 3 * .186=-8.37*10^-3
b) -0.0100* 2* .186= -3.72*10^-3
c)-0.035* ....not it
d)-0.0100* 3*.186= -5.58*10^-3

A MgCl2 has three particles and a molarity of 0.015, multiply the two= biggest number out of all of them

option 2

E)

You can use the known value of osmotic pressure (0.205 atm) to solve the equation pi=i(MRT) where (i) is Van 't Hoff factor (1 since insulin is not ionic) R is the constant 0.0821 L atm / K mol, and T is temperature in Kelvin. So solving you get:

0.205=1(0.08206)(298)
0.205=24.466M
M=0.084

since Molar mass is g/mol.

62.4g/0.0084mol= 7666.67g/mol or round to 7667g/mol inslulin

So answer is B 5000

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