Answer:
a. Plum pudding model
Explanation:
The plum pudding model of the atom was proposed by J.J. Thomson. It was the model he derived from his experiment on the gas discharge tube.
J.J Thomson was the first person to discover electrons which he called cathode rays because in the discharge tube, they emanate from the cathode.
- This led him to suggest the plum pudding model of the atom.
- The model reflects electrons being surrounded by a volume of negative charges.
To calculate how many photons are in a certain amount of energy (joules) we need to know how much energy is in one photon.
Start by using two equations:
Energy of a photon = Frequency * Planck's constant (6.626 * 10^(-34) J-s)
Speed of light (constant 3 * 10^8 m/s) = Frequency * Wavelength
Which means:
frequency = Speed of Light / Wavelength
So energy of a photon = (Speed of light * Planck's constant)/(Wavelength)
You may have seen this equation as E = hc/<span>λ</span>
We have a wavelength of 691 nm or 691 * 10^-9 meters
So we can plug in all of our knowns:
E = (6.626 * 10^(-34) J-s) * (3.00 * 10^8 m/s) / (691 * 10^-9 m) =
2.88 * 10^(-19) joules per photon
Now we have joules per photon, and the total number of joules (0.862 joules)
,so divide joules by joules per photon, and we have the number of photons:
0.862 J/ (2.88 * 10^(-19) J/photon) = 3.00 * 10^18 photons.
Answer:
(A) endothermic
(A) Yes, absorbed
Explanation:
Let's consider the following thermochemical equation.
2 Fe₂O₃(s) ⇒ 4 FeO(s) + O₂(g) ΔH = 560 kJ
Since ΔH > 0, the reaction is endothermic.
We can establish the following relations:
- 560 kJ are absorbed when 2 moles of Fe₂O₃ react.
- The molar mass of Fe₂O₃ is 160 g/mol.
Suppose 66.6 g of Fe₂O₃ react. The heat absorbed is:
Answer:
This question is incomplete, however, the unknown compound can be inferred to be "Lithium Bromide"
Explanation:
The unknown compound firstly is said to be an ionic compound. An ionic/electrovalent compound is a compound in which it's constituent ions transfer/receive electron(s). They are mostly made of group 1 and group 7 elements. Examples include NaCl, NaF, LiF and KCl.
Also, the ion (metallic ion) that produces a red flame test colour in a flame test is the <u>Lithium ion (Li⁺).</u> Also, when dissolved in water or hexane, the only halogen that produces a red/orange colour is bromine. Hence, the unknown ionic compound can be inferred to be Lithium Bromide.
Answer:
Its quite vague, instead you could say an atom is the smallest building block which further consists of subatomic particles like protons, neutrons and electrons :)
Hope thi helps :) and I'd appreciate if you'd mark brainliest because ive been stuck on the same rank for quite a long time :(
