Answer:
Dark matter makes up 85% of the mass of the universe. Dark matter is not directly observable because it doesn't interact with any electromagnetic wave. In the development of the universe, without dark matter, the universe will not function, move or rotate as it does now (this speculation led to the quest to find the anomaly of mass and energy in the known universe, eventually leading to the idealization of dark matter) and will not have enough gravitational force to hold it together. After the big bang,<em> the presence of dark matter and energy ensured that the newly formed universe didn't just float away, rather, it provided enough gravitational force to hold the universe while still allowing it to expand sufficiently</em>.
The development of the universe would have been different without the universe in the sense that the young universe won't have enough mass to hold it together, and the universe would have simply floated apart. The behavior of the universe would have been different from what we observe now, and some physical laws that applies now will not apply to the universe.
There is a missing portion of this question which shows the reaction that needs balancing:
"In a balanced equation, the same number of each kind of atom is shown on each side of the equation. Calculate the number of iron (Fe), oxygen (O), and carbon atoms (C).
Fe2O3+ 3CO --> 2Fe + 3CO<span>2
</span><span>Based on these values, is the equation balanced?</span><span>"
</span>
To check if this equation is balanced we simply compare the number of each element on each side of the equation.
On the reactant side of the equation we have:
2 Fe atoms
6 O atoms
3 C atoms
On the product side of the equation we have:
2 Fe atoms
6 O atoms
3 C atoms
Therefore, both side of the reaction have the correct and equal number of each atom, so the equation is balanced.
Answer: seas
Explanation:
The ancient astronomers thought the mares on the moon were seas.
Answer: Gas. Gas vibrates and move freely at high speeds.
Explanation:
One of the best buffer choice for pH = 8.0 is Tris with Ka value of 6.3 x 10^-9.
To support this answer, we first calculate for the pKa value as the negative logarithm of the Ka value:
pKa = -log Ka
For Tris, which is an abbreviation for 2-Amino-2-hydroxymethyl-propane-1,3 -diol and has a Ka value of 6.3 x 10^-9, the pKa is
pKa = -log Ka
= -log (6.3x10^-9)
= 8.2
We know that buffers work best when pH is equal to pKa:
pKa = 8.2 = pH
Therefore Tris would be a best buffer at pH = 8.0.
