Answer: last option, what came before the big bang?
Explanation:
The big bang theory states that the universe started as a dense nucleus of matter: a huge amount of matter concentrated in a tiny spot.
This is the conclusion of equations and evidences that prove that the universe has been and continuous to expand: since it has been expanding, there was a moment when it was as small and dense as it is possible.
So, the expansion is the result of violent explosion.
The time during which the expansion has been happening (this is how long ago the big bang occured) has been estimated thanks the the observation of the speed of recesion of the galaxies, but nothing can be told about what came before the bing bang occured.
The formula of the given compounds are as follows:
a. copper (II) phosphate : Cu₃(PO₄)₂
b. phosphorus trichloride : PCl₃
c. potassium sulfite : K₂SO₃
d. strontium nitride : Sr₃N₂
e. nitrous acid : HNO₂
<h3>What is the formula of a compound?</h3>
The formula of a compound represents the compound using the symbol of the component elements in the compound showing the ratio in which the atoms of the elements combine in the compound.
The formula of the given compounds are as follows:
a. copper (II) phosphate : Cu₃(PO₄)₂
b. phosphorus trichloride : PCl₃
c. potassium sulfite : K₂SO₃
d. strontium nitride : Sr₃N₂
e. nitrous acid : HNO₂
In conclusion, the formula of a compound represents the compound with symbols.
Learn more about formula of compound at: brainly.com/question/13522594
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The reaction is actually endothermic because delta H is positive, indicating that it absorbing heat.
The formula of Iron(III) oxide is Fe2O3
In order to calculate the mass of iron in a given sample of iron(III) oxide, we must first know the mass percentage of iron in iron(III) oxide. This is calculated by:
[mass of iron in one mole of iron(III) oxide/ mass of one mole of iron(III) oxide] * 100
= [(moles of iron * Mr of iron) / (moles of Iron * Mr of Iron + moles of Oxygen * Mr of Oxygen)] * 100
= [(2 * 56) / (2 * 56 + 3 * 16)] * 100
= (112 / 160) * 100
= 70%
Thus, in a 100g sample, the weight of iron will be:
100 * 70%
= 70 grams
In this kind of exercises, you should use the "ideal gas" rules: PV = nRT
P should be in Pascal:
445mmHg = 59328Pa
1225mmHg = 163319Pa
V should be in cubic meter:
16L = 0.016 m3
R =
= constant
=
==> P1 * V1 = P2 * V2
V2 =
=
V2 = 0.00581 m3 = 5.81 L
