I believe that this problem has 6 questions:
a) Is the reaction endothermic or exothermic?
Why? <span>
b) Calculate the temperature change of the solution in the
calorimeter.
c) Calculate the total mass of the solution in the
calorimeter.
d) Calculate the energy change of the solution.
e) Calculate the energy change of the calorimeter.
f) Calculate the total change of enthalpy of the solution in
kJ/mole.</span>
The answers are the following:
a) This is exothermic because the temperature
of the water increased hence heat energy was released by the reaction.
<span>
b) 33 – 23 = 10C </span>
<span>
c) 100 ml x 1 g/1 ml = 100 g </span>
<span>
d) The formula for change in energy is:</span>
Energy change = mass of solution x temperature
change x specific heat <span>
Energy change = 100 g x 10C x 4.18 Joules/gC = 4,180 Joules </span>
<span>
e) 20 Joules/C x 10C = 200 Joules </span>
<span>
f) First calculate for moles of LiCl: 5.00 g LiCl x 1 mole
LiCl/42.4 g = 0.118 moles
So the total energy given off = 4,180 J + 200 Joules = 4,380
Joules
Enthalpy change, delta H is -4,380
-4380 Joules/0.118 moles = -37,119 Joules/mole
-37,119 Joules/ 1mole x 1 kilojoule/1000 Joules = -37.1
kilojoules
<span>ΔH = -37.1 kJ/mole</span></span>
Answer:
Explanation:
Cubic decimeter is the same unit as liter; so, mole per cubic decimeter is mole per liter, and that is the unit of concentration of molarity. Thus, what is asked is the molarity of the solution. This is how you find it.
1. <u>Take a basis</u>: 1 dm³ = 1 liter = 1,000 ml
2. <u>Calculate the mass of 1 lite</u>r (1,000 ml) of solution:
- density = mass / volume ⇒ mass = density × volume
Here, the density is given through the specific gravity
Scpecific gravity = density of acid / density of water
Take density of water as 1.00 g/ml.
- density of solution = 1.25 g/ml
- mass solution = 1.25 g/ml × 1,000 ml = 1,250 g
3. <u>Calculate the mass of solute</u> (pure acid)
- % m/m = (mass of solute / mass of solution) × 100
- 56 = mass of solute / 1,250 g × 100
- mass of solute = 56 × 1,250g / 100 = 700 g
4. <u>Calculate the number of moles of solute</u>:
- moles = mass in grams / molar mass = 700 g / 70 g/mol = 10 mol
5. <u>Calculate molarity (mol / dm³)</u>
- M = number of moles of solute / liter of solution = 10 mol / 1 liter = 10 mol/liter.
Answer:
Each whole pH value below 7 (the neutral point) is ten times more acidic than the next higher value. For example, a pH of 4 is ten times more acidic than a pH of 5 and 100 times (10 times 10) more acidic than a pH of 6.
Explanation:
The most mass is in my grandmas, because she a big lady. Respectfully.
I guess d correct answer is CaCO3