A negative formation enthalpy means that the reaction is exothermic, or that heat is released during the process.
(C,)
Answer:
-0.276 Degrees C
Explanation:
kf of water is 1.86
Freezing point depression= m x kf x i
i= ions present ( K+ Cl-) 1=2
1.86x2X.743= .276
Since its freezinf point depression the freezing point will lower
so
0-.276= -.276
Answer:
7.81 moles
Explanation:
To solve this problem, let us generate an expression involving volume and number of mole of the gas since the pressure and temperature of the gas are constant.
From ideal gas equation:
PV = nRT
Divide both side by P
V= nRT/P
Divide both side by n
V/n = RT/P
Since RT/P are constant, then:
V1/n1 = V2/n2
Data obtained from the question include:
V1 = 4.11
n1 = 2.51 moles
V2 = 16.9L
n2 =?
Using the above equation i.e V1/n1 = V2/n2, the final number of the gas can be obtained as illustrated below:
4.11/2.51 = 16.9/n2
Cross multiply to express in linear form
4.11 x n2 = 2.51 x 16.9
Divide both side by 4.11
n2 = (2.51 x 16.9) / 4.11
n2 = 10.32moles
Now, to obtain the number of mole of the gas added, we'll subtract the initial mole from the final mole i.e
n2 — n1
Number of mole added = n2 — n1
10.32 — 2.51 = 7.81 moles
Therefore, 7.81 moles of the gas was added to the container
Yep. it is.... sorry for making this a run on but it needs to be 20characters long
Moles HCl reacted : 0.0135
<h3>Further explanation</h3>
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
So to find the number of moles can be expressed as
n = V x M
The volume of HCl 30 cm³=3.10⁻² dm³
Molarity of HCl = 0.45 mol/dm³
so moles HCl reacted :
