What is a hemmoroid?

What is the melting point of a solution in which 3.5 grams of sodium chloride is added to 230 mL of water?

kirza4 [7]

We are going to use this equation:

ΔT = - i m Kf

when m is the molality of a solution

i = 2

and ΔT is the change in melting point = T2- 0 °C

and Kf is cryoscopic constant = 1.86C/m

now we need to calculate the molality so we have to get the moles of NaCl first:

moles of NaCl = mass / molar mass

= 3.5 g / 58.44

= 0.0599 moles

when the density of water = 1 g / mL and the volume =230 L

∴ the mass of water = 1 g * 230 mL = 230 g = 0.23Kg

now we can get the molality = moles NaCl / Kg water

=0.0599moles/0.23Kg

= 0.26 m

∴T2-0 = - 2 * 0.26 *1.86

∴T2 = -0.967 °C

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3 years ago

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Iron(II) chloride is formed from the reaction between iron and copper(II) chloride. Fe + CuCl2 FeCl2 + Cu If the reactants have

elena55 [62]

Answer: see figure attached and explanation below.

Explanation:

1) Chemical equation (given):

Fe + CuCl₂ → Cu + FeCl₂

2) ΔHf reactants: -256 kJ/mol (given)

3) ΔHf products: - 321 kJ/mol (given)

4) ΔH reaction = ΔHf products - ΔHf reactants = - 321 kJ/mol - (- 256 kJ/mol) = - 65 kJ/mol

5) Conclusion:

i) Since ΔHf of products is less (more negative) than ΔHf of reactants, the reaction is exhotermic: the reaction released energy, which is the reason why the products content less potential energy than the reactants.

ii) Then, the energy diagram is the typical one of an exothermic reaction: the products start a certain potential energy level, the energy incrases until reaching the activation energy (the energy barrier to form the activated complex) and then energy decreases until a level below the energy of the reactants.

iii) See the attached figure with such kind of diagram showing the products at a lower level than the reactans