Answer:
1.373 wt% Ca(OH)₂
Explanation:
Sample mix = 15.0g
Ca(OH)₂(aq) + 2HCl(aq) => CaCl₂(aq) + 2H₂O(l)
moles HCl = 0.2000g / 36 g·mol⁻¹ 0.0056 mol
moles Ca(OH)₂ = 1/2(moles HCl) = 1/2(0.0056 mol) = 0.0028 mol
mass Ca(OH)₂ = 0.0028 mol ( 74 g/mol ) = 0.206 g
mass % Ca(OH)₂ = (0.206/15.0)100% = 1.373 wt%
I choose the letter c witch is density I believe that it’s useful for determining identifying relationships between substances
A asystem at equilibrium stops
Answer:
51.54°C the final temperature of the calorimeter contents.
Explanation:


Molarity of HCl= 0.50 M
Volume of HCl= 150.0 mL = 0.150 L
Moles of HCl= n

Molarity of NaOH= 1.00 M
Volume of NaOH= 50.0 mL = 0.050 L
Moles of NaOH= n'

Since moles of NaOH are less than than moles of HCl. so energy release will be for neutralization of 0.050 moles of naOH by 0.050 moles of HCl.
n = 0.050


(1 kJ= 1000 J)
The energy change released during the reaction = 2800 J
Volume of solution = 150.0 mL + 50.0 mL = 200.0 mL
Density of the solution (water) = 1.00g/mL
Mass of the solution , m= 200 mL × 1.00 g/mL = 200 g
Now , calculate the final temperature by the solution from :

where,
q = heat gained = 2800 J
c = specific heat of solution = 
= final temperature = 
= initial temperature = 
Now put all the given values in the above formula, we get:


51.54°C the final temperature of the calorimeter contents.
<u>Answer:</u> The amount of heat absorbed by the solution is 2.795 kJ
<u>Explanation:</u>
To calculate the mass of water, we use the equation:

Density of water = 1 g/mL
Volume of water = [70 + 70] = 140 mL
Putting values in above equation, we get:

To calculate the heat absorbed, we use the equation:

where,
q = heat absorbed
m = mass of water = 140 g
c = heat capacity of water = 4.186 J/g°C
= change in temperature = 
Putting values in above equation, we get:

Hence, the amount of heat absorbed by the solution is 2.795 kJ