Carbon and Hydrogen are present in all organic compounds !
Answer:
The temperature change was 10.04 °C.
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system. In this way, there is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case you know:
- c= 1
Replacing:
7,529 cal= 1 *750 g* ΔT
Solving you get:
ΔT=
ΔT= 10.04 °C
So, <u><em>the temperature change was 10.04 °C.</em></u>
Answer: E) In a closed system, the total energy always remains constant.
Explanation: For every system, the law of conservation of energy is applicable which states that the energy of the system remains conserved. Energy can neither be created nor destroyed.
A closed system is one which can exchange energy with the surroundings but not mass. Thus if a system absorbs energy, the equivalent amount of energy is lost by surroundings, thus the total energy remains constant.
If a system loses energy, an equivalent amount of energy is gained by surroundings, thus the total energy remains constant.
From the calculations, the pH of the final solution is 9.04.
<h3>What is the pH of the buffer?</h3>
We can use the Henderson Hasselbach equation to obtain the final pH of the solution in terms of the pKb and the base concentration.
Number of moles of salt = 250/1000 L * 0.5 M = 0.125 moles
Number of moles of base = 150/1000 L * 0.5 M = 0.075 moles
Total volume of solution = 250ml + 150ml = 400ml or 0.4 L
Molarity of base = 0.075 moles/ 0.4 L = 0.1875 M
Molarity of salt = 0.125 moles/ 0.4 L = 0.3125 M
pOH = pKb + log[salt/base]
pKb = -log(1.8 x 10^-5) = 4.74
pOH = 4.74 + log[0.3125/0.1875 ]
pOH = 4.96
pH = 14- 4.96
pH = 9.04
Learn more about pH:brainly.com/question/15289741
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Remember that the number of protons in the nucleus determines an element's identity. Chemical changes do not affect the nucleus, so chemical changes cannot change one type of atom into another. The number of protons in a nucleus does change sometimes, however. The identity of the atom, therefore, changes.
