Answer:
d. The energy required to evaporate 1 kg of liquid water equals the energy released when 1 kg of water vapor condenses into liquid.
Explanation:
Hello,
Since we're considering the same amount of water, the vapor phase has a higher energy content than the liquid phase, thus, for the specified amount of water particles (those contained in the given 1 kg) the energy MUST be same when taking them either to a gaseous phase or to a liquid phase, the only difference is the sign which is negative from gaseous to liquid (heat withdrawal) and positive from liquid to gaseous (heat adding).
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Answer:
45.77 × 10²³ atoms
Explanation:
Given data:
Number of moles of iron = 7.6 mol
Number of atoms = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
7.6 mol × 6.022 × 10²³ atoms / 1 mol
45.77 × 10²³ atoms
Answer:
a. positive
b. negative
c. positive
d. negative
Explanation:
In a exothermic reaction, heat is written as a product (del H is negative), whereas in an endothermic reaction heat is written on the reaction side (del H is positive).
For a, it is endothermic process. We know this because to go from solid to liquid you need to put energy into the system. When we put energy into a chemical system it is said to be an endothermic reaction.
For b, it is exothermic reaction. This is because you have to lose the extra energy to go from less ordered states (gas) to more ordered state (liquid). Gas is less ordered because its molecules are freely moving and such. Another way of thinking about this question is just putting the heat on product side and think if I was going in reverse direction I would put heat in product because I would need to add heat to liquid to turn to gas (and if heat is added to product side we know its exothermic). Two ways of thinking whichever you prefer.
The rest have similar explaination.
When an atom emits a beta
particle from the nucleus, the nucleus only has one more proton and one less
neutron and this will make the atomic mass number remains unchanged while the
atomic number increases by 1.
<span>I hope this answer helps you!</span>
