Answer:
Most stars are rather simple things. They come in a variety of sizes and temperatures, but the great majority can be characterized by just two parameters: their mass and their age. (Chemical composition also has some effect, but not enough to change the overall picture of what we will be discussing here. All stars are about three-quarters hydrogen and one-quarter helium when they are born.)
Answer:
Element symbol: Kr.
Mass number: 77.
Charge : 0.
Explanation:
Hello,
In this case, since such substance has the same amount of protons and electrons we can infer it is an atom whose number of neutrons is defined by considering its atomic mass or mass number and atomic number which is actually equal to the number of protons and electrons (36):
In such a way, solving for the atomic mass we obtain:
It means that the element is krypton (Kr) as it has 36 electrons and protons so its charge is 0.
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Answer:
gravaity is the force that helps you
Answer:
25.7 kJ/mol
Explanation:
There are two heats involved.
heat of solution of NH₄NO₃ + heat from water = 0
q₁ + q₂ = 0
n = moles of NH₄NO₃ = 8.00 g NH₄NO₃ × 1 mol NH₄NO₃/80.0 g NH₄NO₃
∴ n = 0.100 mol NH₄NO₃
q₁ = n * ΔHsoln = 0.100 mol * ΔHsoln
m = mass of solution = 1000.0 g + 8.00 g = 1008.0 g
q₂ = mcΔT = 58.0 g × 4.184 J°C⁻¹ g⁻¹ × ((20.39-21)°C) = -2570.19 J
q₁ + q₂ = 0.100 mol ×ΔHsoln – 2570.19 J = 0
ΔHsoln = +2570.19 J /0.100 mol = +25702 J/mol = +25.7 kJ/mol
Answer:
Advantages: More land has been made available for development. More buildings and infrastructure can be built, and also for other reasons.
Disadvantages: Much greenery has been removed in order for the land needed. Land reclamation can be damaging to corals and marine life. Corals are usually moved to another place when land is to be reclaimed. The corals might not be able to survive in that certain habitat, and thus die out. In some countries, where the project is large-scale, they do not even bother to re-plant the corals elsewhere, instead just reclaim the land on their habitat, causing them to die out immediately. Marine life, such as fishes, might not have enough food after the underwater plantations are destroyed due to reclamation of land. This applies to the food chain. The waters might also be polluted from the soil used to reclaim land, causing the fishes to die and blocking out sunlight, depriving the underwater plants of growth. Marine habitats are also destroyed, as mentioned earlier; therefore, the marine creatures would be forced to move to another new habitat. Some might not be able to adapt, and thus die out. Some would just die without even finding a new habitat, as they cannot move long distances in water. Of course, the reasons and examples look tempting to us humans, but marine life is life too! We should try to protect is as much as possible, instead of just focusing on the advantages.
