B. Earth’s tilt
Earth’s tilt exposes different parts of the earth to varying degrees of sunlight throughout the year, causing seasons.
Answer:
sigma bond
represents two electrons
Explanation:
The bond between hydrogen and oxygen is sigma bond because the bond between hydrogen and oxygen is covalent means sharing of electron takes place between two atoms and we know that sigma bond is also occurs in a covalent bond in which overlapping of atomic orbitals or hybrid orbitals along the bond axis occurs. Both also represent two electrons because both atoms share one electron each so we can say that the two atoms represents two electrons.
The units of density are g/ml. If you find the grams of 1 mol of ethanol (with the molecular weight), you can then divide by the density to get the ml of ethanol.
g*(ml/g)=ml
Animals and plants use their cells by growing and observing food and oxygen
Answer:
(a)²⁴²₉₄Pu ⇒ ⁴₂He + ²³⁸₉₂U ⇒ ²³⁸₉₂U + ⁰₀γ
(b) 4.898 MeV
Explanation:
In the nuclear reaction, it was stated that plutonium-242 decayed firstly to uranium-238 and alpha, and lastly to a stable uranium-238 by emitting a gamma ray. The balanced equation for the nuclear reactions is shown below:
(a)²⁴²₉₄Pu ⇒ ⁴₂He + ²³⁸₉₂U ⇒ ²³⁸₉₂U + ⁰₀γ
(b) The energy emitted by releasing a gamma ray is calculated using:
E = hc/λ
where
h = 4.136*10^-15 eV.s
c = 299792458 m/s
λ = 0.02757 nm = 0.02757*10^-9 m
Therefore:
E = (4.136*10^-15)*(299792458)/0.02757*10^-9 = 44974.31 eV
The total energy if the stable 238U was produced directly would be
4.853*10^6 + 44974.31 = 4.898 MeV
