It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms.
These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.
Answer:
CaCO₃(s) → CaO(s) + CO₂(g)
Explanation:
The decomposition reaction always make two compounds from one.
The products always have simpler chemical structure, originated from a determined compound. This can happens spontaneously or by a third party.
A notable example of decomposition is hydrolysis. As for example the case of water, which decomposes and generates oxygen and hydrogen gas
2H₂O (l) → 2 H₂ (g) + O₂ (g)
In this case, the calium carbonate decomposes into CaO and CO₂
These two, are the products of the decomposition.
Of course, the unique reactant is the Calcium Carbonate
The balanced equation is:
CaCO₃(s) → CaO(s) + CO₂(g)
Answer:
C2H5NO
Explanation:
constituent elements N O C H
Mass composition 0.420 0.480 0.540 0.135
mole ratio 0.42/14 0.48/16 0.54/12 0.135/1
= 0.03 0.03 0.045 0.135
dividing by the smallest 0.03/0.03 0.03/0.03 0.045/0.03 0.135/0.03
ratio = 1 1 1.5 4.5
= 1 1 2 5
EMPERICAL FORMULA = C2H5NO
When it comes to physical changes like phase changes, there are two types of heat energy: sensible heat and latent heat. Sensible heat is the heat absorbed/released when you heat the substance but it doesn't change phase. An example would be heating lukewarm water. The substance is liquid all throughout. Latent heat, on the other hand, is the heat absorbed/released when there is a phase change. An example would be boiling water, because it changes liquid to vapor.
Hence, for freezing liquid, you use the latent heat, specifically the heat of fusion. The answer should be
2.5 g * (1 mol/18.02 g) * 6.03 kJ/mol = 0.84 kJ/mol
The answer is not in the choices. You only use Hvap if you boil water.
Answer:
As temperature increases the volume of given amount of gas increases while pressure and number of moles remain constant.
Explanation:
According to the charle's law,
The volume of given amount of gas is directly proportional to the temperature at constant pressure and number of moles of gas.
Mathematical expression:
V ∝ T
V = KT
V/T = K
When temperature changes from T₁ to T₂ and volume changes from V₁ to V₂.
V₁/T₁ = K V₂/T₂ = K
or
V₁/T₁ = V₂/T₂
Thus, the ratio of volume and temperature remain constant for constant amount of gas at constant pressure.
