Answer: In simplest case mass of reactants is same as mass of products.
Without thinking this question deeper, mass of ZnCl2 would be 49, but..
Explanation: Reaction should be Zn + 2 HCl ⇒ ZnCl2 + H2
Amount of zinc is 5 g / 65,38 g/mol = 0,076476 mol and amount
of Hydrogen Chloride is 50 g / 36.458 g/mol = 1,371 mol.
Althought HCl is needed 0.152 moles, zinc is an limiting reactant.
So it is possible to produce only 0.076476 mol Hydrogen and its mass
is 0.154 g. Mass of ZnCl2 would be 0.076476 mol · (65.38 + 2·35.45) =
10.42 g
The two types of energy changes that occur are heat and light changes.
<u>Answer:</u> The freezing point of solution is 5.35°C
<u>Explanation:</u>
The equation used to calculate depression in freezing point follows:

To calculate the depression in freezing point, we use the equation:

Or,

where,
Freezing point of pure solution = 5.5°C
i = Vant hoff factor = 1 (For non-electrolytes)
= molal freezing point elevation constant = 4.90°C/m
= Given mass of solute (naphthalene) = 2.60 g
= Molar mass of solute (naphthalene) = 128.2 g/mol
= Mass of solvent (benzene) = 675 g
Putting values in above equation, we get:

Hence, the freezing point of solution is 5.35°C
Answer:
[NaCl]: 2M
Explanation:
This solution is made of NaCl therefore:
Our solute is NaCl
Moles of solute: 4
Our solution's volume is 2L
Molarity are the moles of solute contained in 1L of solution (mol/L)
[NaCl]: 4 mol /2L = 2M
We can also make a rule of three:
In 2 L we have 4 moles of solute
So, In 1 L we must have (1 . 4) /2 = 2 M
Enthalpy change during the dissolution process = m c ΔT,
here, m = total mass = 475 + 125 = 600 g
c = <span>specific heat of water = 4.18 J/g °C
</span>ΔT = 7.8 - 24 = -16.2 oc (negative sign indicates that temp. has decreases)
<span>
Therefore, </span>Enthalpy change during the dissolution = 600 x 4.18 X (-16.2)
= -40630 kJ
(Negative sign indicates that process is endothermic in nature i.e. heat is taken by the system)
Thus, <span>enthalpy of dissolving of the ammonium nitrate is -40630 J/g</span>