Answer:
7. A) I, II
; 8. D) 2.34e9 kJ
Step-by-step explanation:
7. Combustion of ethanol
I. The negative sign for ΔH shows that the reaction is exothermic.
II. The enthalpy change would be different if gaseous water were produced.
That's because it takes energy to convert liquid water to gaseous water, and this energy is included in the value of ΔH.
III. The reaction is a redox reaction, because
- Oxygen is reacting with a compound
- The oxidation number of C increases
- The oxidation number of O decreases.
IV. The products of the reaction occupy a smaller volume than the reactants, because 3 mol of gaseous reactant are forming 2 mol of gaseous product.
Therefore, only I and II are correct.
7. Hindenburg
Data:
V = 2.00 × 10⁸ L
p = 1.00 atm
T = 25.1 °C
ΔH = -286 kJ·mol⁻¹
Calculations:
(a) Convert temperature to kelvins
T = (25.1 + 273.15) K = 298.25 K
(b) Moles of hydrogen
Use the <em>Ideal Gas Law</em>:
pV = nRT
n = (pV)/(RT)
n = (1.00 × 2.00 × 10⁸)/(0.082 06 × 298.25) = 8.172 × 10⁶ mol
(c) Heat evolved
q = nΔH = 8.172 × 10⁶ × (-286) = -2.34 × 10⁹ kJ
The hydrogen in the Hindenburg released 2.34e9 kJ
.
We first calculate the heat released:
Specific heat = 3.21 kJ/kgK
Heat released = heat absorbed by calorimeter
Heat absorbed = mcΔT
= 1.9 x 3.21 x 4.542
= 27.7 kJ
Now, we calculate the moles of hexane present:
Moles = mass / Mr
moles = 0.58 / (12 x 6 + 14)
= 0.0067
Heat of combustion = 27.7 / 0.0067 kJ/mol
ΔH(combustion) = 4,134.3 kJ / mol
the understanding of dehidatianismistering can be difficult in the modern world created for these specific terms
Answer:Maintaining resting potential and returning to resting potential after the hyperpolarization phase of an action potential
Explanation:TOXINS are chemical substances which are known to be POISONOUS produced with living organisms that causes harm to other organisms, examples include Venom from snakes which when a person is bitten by a Snake it will possibly lead to death if not adequate treated.
HYPERPOLARIZATION is a term that explains the change in membrane potential due to toxin,it make the membrane more electronegative. When the toxin has hyped the level of Sodium-Potassium level returning to a rest state will be most affected.
The heat of reaction is 1.8 KJ. A calorimeter is a device used in calorimetry, a procedure for calculating heat capacity and measuring the heat of chemical processes or other physical changes.
<h3>How to calculate calorimeter?</h3>
- A calorimeter is a device used in calorimetry, a procedure for calculating heat capacity and measuring the heat of chemical processes or other physical changes.
- Among the most popular kinds are differential scanning calorimeters, isothermal micro calorimeters, titration calorimeters, and accelerated rate calorimeters.
- Calorimeter, a tool for estimating a material's heat capacity and measuring the heat produced during a mechanical, electrical, or chemical reaction. bomb thermometer.
Volume of water = 67.9 mL
Since the density of water is 1.00 g/mL
Density = mass/volume
Mass of water = Density × volume
Mass of water = 1 g/mL × 67.9 mL
Mass of water = 67.9g or 0.0679 Kg
Temperature change = 6.5 oC
Specific heat capacity of water= 4.184 J/Kg
From;
H = mcθ
m = mass of water
c = heat capacity of water
θ = temperature rise
Substituting values;
H = 0.0679 Kg × 4.184 J/Kg × 6.5 oC
H = 1.8 KJ
To learn more about calorimeter refer to:
brainly.com/question/1407669
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