Answer:Static electricity works because objects which are otherwise "neutral" (in other words, objects with no net charge) can be polarized. An electric field, like one caused by a nearby charged object, can cause the charges inside of a neutral object — the protons and electrons — to move around a tiny bit.
Explanation:
The energy change if 84.0 g of CaO react with excess water is 98KJ of heat is released.
calculation
heat = number of moles x delta H
delta H = - 65.2 Kj/mol
first find the number of moles of CaO reacted
moles = mass/molar mass
the molar mass of CaO = 40 + 16= 56 g/mol
mass = 84 g
moles therefore = 84 g/56 g/mol =1.5 moles
Heat is therefore = 1.5 moles x -65.2 = - 97.8 Kj = -98 Kj
since sign is negative the energy is released
Answer:
Data is not valid
Explanation:
When two liquids having different temperatures are mixed, regardless of the volumes, the final mix temperature will ALWAYS be between the initial temperature values.
1st Law Thermo => Law of Conservation of Energy => Energy can not be created nor destroyed, only changed in form. Mixing 22°C with 75°C will NOT result in a mix having a final temperature of 80°C.
∑ΔE = 0 => (mcΔT)₁ + (mcΔT)₂ = 0
[(20g)(1cal/g·°C)(Tₓ - 22°C)] + [(80g)(1cal/g·°C)(Tₓ - 75°C)] = 0
=> 20(Tₓ - 22) + 80(Tₓ - 75) = 0
=> 20Tₓ - 440 + 80Tₓ - 75 = 0
=> 100Tₓ = 440 + 75 = 515
=> Tₓ = (515/100)°C = 51.5°C final mix temperature
Phosphorus dissolving in carbon disulfide is a physical change.
A chemical change results from a chemical reaction, in which the nature of the substance is altered. On the other hand, a physical change is when matter changes forms but not chemical identity.
When phosphorus dissolves in carbon disulfide, it changes its state of aggregation, but not its nature. Thus, this is a physical change.
Phosphorus dissolving in carbon disulfide is a physical change.
You can learn more about physical and chemical changes here: brainly.com/question/13620149
