Answer:
- Question 19: the three are molecular compounds.
Explanation:
<em>Question 19.</em>
All of them are the combination of two kinds of different atoms in fixed proportions.
- C₂H₄: two carbon atoms per four hydrogen atoms
- HF: one hydrogen atom per one fluorine atom
- H₂O₂: two hydrogen atoms per two oxygent atoms
Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.
Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.
Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.
<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.
Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol
Water is H₂O. Its molar mass is 18.015g/mol
Calling x the number of water molecules in the hydrate, the percentage of water is:
From which we can solve for x:
Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:
The following are the statements, which indicates that the fossil record suggests about evolution on Earth:
1. Humans have only recently existed on Earth.
2. The organisms originally lived only in Earth's water.
3. The plants did not have flowers when dinosaurs existed.
The fossil remains have been discovered in the rocks of all the ages. The simplest organisms fossils are witnessed in the oldest rocks, and the fossils of more composite species are found in the newest rocks. This supports the theory of evolution suggested by Darwin, according to which the simple life forms slowly gets evolved into more composite ones.
Answer:
large, released
Explanation:
As we know, fireworks contain l o t s of energy, even before the burst of colors release. So i think choice 3 is the answer.
i hope this helps :)
<span>This is not the case in the hydrocarbon tail. The electronegativity of hydrogen and carbon are very similar, so the electron cloud is distributed evenly over the two atoms. Carbon-hydrogen bonds are said to be non-polar because they do not have positive and negative poles within themselves. Hope this helps. </span>
The temperatures of the gases will not be equal as oxygen gas will have a higher temperature than hydrogen gas because it has fewer moles overall.
<h3>Briefing :</h3>
The mechanical behavior of ideal gases is described by the ideal gas law. It has the ability to compute the volume of gases created or absorbed.
This equation is frequently used in chemical equations to convert between volumes and molar quantities.
According to the ideal gas law, there is a relationship between gas pressure, temperature, and volume.
PV = nRT
V is the same for both
So,
T is same for both.
When n increases, T decreases, so since n for hydrogen gas is 1 and n for oxygen gas is 0.5, it follows that oxygen gas will have a higher temperature than hydrogen gas because it has fewer moles overall.
To know more about ideal gases :
brainly.com/question/15962335
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