It took me a while to understand what u we’re trying to say
Answer:
Q = 1.5 kJ
Explanation:
It is given that,
The specific heat for aluminum is 0.900 J/g°C
Mass of sample, m = 3.8 g
Initial temperature,
Final temperature,
We need to find the heat released. The amount of heat released is given by the formula:
or
So, the correct option is (A) i.e. 1.5 kJ.
We need to first find the molarity of Ba(OH₂) solution.
A mass of 3.24 mg is dissolved in 1 L solution.
Ba(OH)₂ moles dissolved - 3.24 x 10⁻³ g/171.3 g/mol = 1.90 x 10⁻⁵ mol
dissociaton of Ba(OH)₂ is as follows;
Ba(OH)₂ --> Ba²⁺ + 2OH⁻
1 mol of Ba(OH)₂ dissociates to form 2OH⁻ ions.
Therefore [OH⁻] = (1.90 x 10⁻⁵)x2 = 3.8 x 10⁻⁵ M
pOH = -log[OH⁻]
pOH = -log (3.8 x 10⁻⁵)
pOH = 4.42
pH + pOH = 14
therefore pH = 14 - 4.42
pH = 9.58
We need two pieces of information to calculate the reduction of the
vapor pressure of the solvent in a solution containing a nonvolatile
nonelectrolyte:
<span>
<span>The mole fraction of the
nonvolatile solute, Xsolute, in the solution.</span>
<span>The vapor pressure of the
pure solvent, Psolv.</span>
</span>
Psoln = Psolvent (1- Xsolute)
Xsolute = (100g /342.3 g/ mol) / ( 100g
/342.3 g/ mol) + (250 g/ 18 g/ mol)
X solute = 0.0206
P soln = (23.8 mmHg) (1- 0.0206)
Psoln = 23.31 mmg Hg
<span> </span>