Enthalpy change is the term given to the concentration of the heat absorbed or evolved in a reaction carried out at a constant pressure. It is given by the symbol ΔH.
Enthalpy change = m (Cwater × dT + Hvap + Csteam × dT
dHvap = 40.67 kJ/mol = 40.67 × 103/18 = 2259.4 J/g
Enthalpy change = 5.00 [4.18 × (100-14) + 2259.4 + 1.84 × (115-100)]
= 13232.4 J
Answer:
C
Explanation:
A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.
A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.
Answer:
In a nuclear fusion reaction, the nuclei of two atoms combine to create a new atom. Most commonly, in the core of a star, two hydrogen atoms fuse to become a helium atom. Although nuclear fusion reactions require a lot of energy to get started, once they are going they produce enormous amounts of energy.
Explanation:
If the reaction is represented by:
PCl₃ + Cl₂ <-> PCl₅ (exothermic)
the mole fraction of chlorine in the equilibrium mixture will change according to the following:
Decrease the volume: decrease
Increase the temperature: increase
Increase the volume: increase
Decrease the temperature: decrease
Answer:
Correct answer is A.
Explanation:
Frequency is the number of oscillations that a wave have per unit time. Since time is measured in seconds, the wave with the highest frequency must register the highest number of oscillation per second. Hence, correct answer is A.
