I think Both protons and neutrons (and their anti-particles) froze out at 1013 K, about 0.0001 seconds after the Big Bang. Protons and neutrons are sub atomic particles of an atom that are found in the nucleus of an atom. Proton is the positively charge particle while the neutron has no charge. The proton positive charge accounts for the positive nuclear charge.
The statement that is true is that B. Atoms always remain intact during chemical reactions.
Atoms simply mean the <u>basic units of matter.</u> They're the defining structure of an element. Atom is also known as the smallest unit of matter.
It should be noted that atoms always remain intact during chemical reactions. They cannot be added and removed when there are <em>chemical reactions.</em>
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675 nanograms is equivalent to 6.75 × 10-⁴ milligrams.
<h3>How to convert nanograms to milligrams?</h3>
Nanograms is a unit of mass equal to 0.000000001 grams and has a symbol of ng.
On the other hand, milligrams is another unit of mass equal to 0.001grams and has a symbol of mg.
Nanograms and milligrams are both units of mass and can be inter-convertible as follows:
1 nanogram = 1 × 10-⁶ milligram
According to this question, 675 nanograms is equivalent to 675 × 10-⁶ milligrams.
Therefore, 675 nanograms is equivalent to 6.75 × 10-⁴ milligrams.
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a. 381.27 m/s
b. the rate of effusion of sulfur dioxide = 2.5 faster than nitrogen triiodide
<h3>Further explanation</h3>
Given
T = 100 + 273 = 373 K
Required
a. the gas speedi
b. The rate of effusion comparison
Solution
a.
Average velocities of gases can be expressed as root-mean-square averages. (V rms)

R = gas constant, T = temperature, Mm = molar mass of the gas particles
From the question
R = 8,314 J / mol K
T = temperature
Mm = molar mass, kg / mol
Molar mass of Sulfur dioxide = 64 g/mol = 0.064 kg/mol

b. the effusion rates of two gases = the square root of the inverse of their molar masses:

M₁ = molar mass sulfur dioxide = 64
M₂ = molar mass nitrogen triodide = 395

the rate of effusion of sulfur dioxide = 2.5 faster than nitrogen triodide
Answer:
The difference between the density of the ocean crust and the continental crust is the fact that the ocean crust is denser than the continental crust. Meaning, the continental crust is likely to push over the oceanic crust considering it has less dense.
Explanation:
I hope this helps, the last time I learned this was in 5th grade and I am i currently in the 11th grade....