Answer is: molality od sodium chloride is 2,55 mol/kg.
V(solution) = 100 ml.
m(solution) = d(solution) · V(solution).
m(solution) = 1,10 g/ml · 100 ml.
m(solution) = 110 g.
ω(NaCl) = 13,0% = 0,13.
m(NaCl) = ω(NaCl) · m(solution).
m(NaCl) = 0,13 · 110 g.
m(NaCl) = 14,3 g.
n(NaCl) = m(NaCl) ÷ M(NaCl).
n(NaCl) = 14,3 g ÷ 58,5 g/mol.
n(NaCl) = 0,244 mol.
m(H₂O) = 110 g - 14,3 g.
m(H₂O) = 95,7 g = 0,0957 kg.
b(NaCl) = n(NaCl) ÷ m(H₂O).
b(NaCl) = 0,244 mol ÷ 0,0957 kg.
b(NaCl) = 2,55 mol/kg.
Answer:
Not sure what the answer is
Explanation:
I did this a while ago and dont remember sorry
Answer:
The correct answer is option C, that is, ΔS and ΔSsurr for the process H2O (s) ⇒ H2O(l) are equal in magnitude and opposite in sign.
Explanation:
The temperature at which solid state of water get transformed into liquid state is termed as the melting point of 0 °C. It can be shown by the reaction:
H2O (s) ⇒ H2O (l)
The degree of randomness of a molecule is known as entropy. With the transformation of ice into liquid state, there is an increase in randomness. Thus, the value of entropy becomes positive as shown:
Entropy change (ΔSsys) = ΔSproduct - ΔSreactant
= (69.9 - 47.89) J mol/K
= 22.0 J mol/K
Therefore, the value of entropy change is positive.
Now the value of entropy for surrounding ΔSsurr will be,
ΔSsurr = -ΔHfusion/T
= -6012 j/mol/273
= -22.0 J/molK
Hence, the value of ΔSsurr and ΔSsys exhibit same magnitude with opposite sign.
For the presence of ammonium ion, there is a need to add sodium hydroxide solution to the water and warm the mixture. Test any vapor that gets produced with damp red litmus paper. It should turn blue as ammonia gas is discharged, which is alkaline. The ionic equation for the reaction is:
NH₄⁺ + OH⁻ ⇒ NH₃ + H₂O
For the presence of phosphate ions, the addition of barium ions is done. The ionic equation is:
3Ba₂⁺ + 2PO4³⁻ ⇒ Ba₃ (PO₄)₂ (precipitate)
Answer:
In a favorable reaction, the free energy of the products is less than the free energy of the reactants.
Explanation:
The free energy of a system is the amount of a system's internal energy that is available to perform work. The different forms of free energy include Gibbs free energy and Helmholtz free energy.
In a system at constant temperature and pressure, the energy that can be converted into work or the amount of usable energy in that system is known as Gibbs free energy. In a system at constant temperature and volume, the energy that can be converted into work is known as Helmholtz free energy.
The change in free energy of a system is the maximum usable energy that is released or absorbed by a system when it goes from the initial state (i.e., all reactants) to the final state (i.e., all products).
In a chemical reaction, some bonds in the reactants are broken by absorbing energy and new bonds are formed in the products by releasing energy. As the reaction proceeds, the free energy of reactants is much greater than the products. As the products are formed, the concentration of reactants decreases and the difference in their free energy also decreases. This chemical reaction will occur until chemical equilibrium is achieved i.e., the free energy of the products and reactants is equal and the difference in their free energy is zero.
