To determine the standard heat of reaction, ΔHrxn°, let's apply the Hess' Law.
ΔHrxn° = ∑(ν×ΔHf° of products) - ∑(ν×ΔHf° of reactants)
where
ν si the stoichiometric coefficient of the substances in the reaction
ΔHf° is the standard heat of formation
The ΔHf° for the substances are the following:
CH₃OH(l) = -238.4 kJ/mol
CH₄(g) = -74.7 kJ/mol
O₂(g) = 0 kJ/mol
ΔHrxn° = (1 mol×-74.7 kJ/mol) - ∑(1 mol×-238.4 kJ/mol)
ΔHrxn° = +163.7 kJ
The correct answers are :
Changing the volume of the system.
Changing the temperature of the system.
Equilibrium will remain unaffected if the concentration of products and reactants are kept the same, and the temperature of the system is kept constant.
As the system is closed, we cannot add or remove products or reactants.
Change in temperature will shift the chemical equilibrium towards the reactant or product depending on whether the reaction is exothermic or endothermic.
Also change in volume will shift the chemical equilibrium of a chemical reaction if the reactants or products or both are gases.
10. You demonstrated the difference in density of the two objects. It is a physical property.
11. First calculate the density for all of them: density = mass/volume
Density:
A. 5/6 g/ml
B. 10/9 g/ml
C. 15/16 g/ml
D. 20/10 g/ml
If the density of the substance is higher than the density of the substance it is put in, then it will sink. So substances B and D will sink in water, as their densities are higher than 1 g/ml.
12. Ammonia weighs less than water does-- for example, the weight of 8 gallons of ammonia will be equivalent to the weight of 5 gallons of water.
Hope this helped!
Answer: 10L
Explanation:
Given that:
Initial pressure P1 = 1 atm
New pressure P2 = 3 atm
Initial volume V2 = 30 L
New volume V2 = ?
Since pressure and volume are involved, apply the formula for Boyle's law
P1V1 = P2V2
1 atm x 30L = 3 atm x V2
30 atm L = 3 atm x V2
V2 = (30 atm L / 3 atm)
V2 = 10L
Thus, volume changed to 10 liters
E = mc^2
E = 8.90 * 10^12 Joules
c = 3 * 10^8 m/s
m = ????
8.90 * 10^12 = m * (3 * 10^8)^2
8.90 * 10^12 = m * 9 * 10^16
9.889 * 10^-4 kg = m <<<<< answer
