By the second law of thermodynamics:
Heat can not spontaneously flow from cold regions to hot regions without external work being performed on a system.
Heat transfer is the passage of thermal energy from a hot ( t B = 80° C ) to a colder body ( t A = 40° C ).
Answer: B ) Heat flows from object B to object A.
<u>Answer:</u> The molarity of calcium hydroxide in the solution is 0.1 M
<u>Explanation:</u>
To calculate the concentration of base, we use the equation given by neutralization reaction:
where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is 
We are given:
Putting values in above equation, we get:
Hence, the molarity of in the solution is 0.1 M.
The formation of nitric acid from nitrogen, hydrogen, and oxygen can be written as,
N₂ + H₂ + 3O₂ --> 2HNO₃
The net enthalpy of formation of nitric acid is calculated by,
Hrxn = Hproduct - Hreactant
Since all the reactants are in their elemental forms, the simplified equation would be,
Hrxn = Hproduct
Substituting,
Hrxn = (-186.81 kJ/mol)(2 mols)
<em>Answer: -372.42 kJ</em>
Answer:
12.50g
Explanation:
T½ = 2.5years
No = 100g
N = ?
Time (T) = 7.5 years
To solve this question, we'll have to find the disintegration constant λ first
T½ = In2 / λ
T½ = 0.693 / λ
λ = 0.693 / 2.5
λ = 0.2772
In(N/No) = -λt
N = No* e^-λt
N = 100 * e^-(0.2772*7.5)
N = 100*e^-2.079
N = 100 * 0.125
N = 12.50g
The sample remaining after 7.5 years is 12.50g
