Melting, or the change of physical states, is the change of distance between particles. In solid state, particles are closely packed together. Energy is required to separate them in order to make it become liquid or even gas.
When a substance has a high melting point, it means the intermolecular forces or the chemical bonds are strong and the particles are easily attracted to each other. Therefore, more energy is needed to overcome these forces. A higher temperature could provide such energy.
Elements are combined together by different kinds of bonds. Ionic bonds and metallic bonds are considered to be strong. Ionic compounds (eg. NaCl) and metals tend to have a high melting point. In covalent compounds, molecules are held by weak van der Waals’ force. Thus, covalent compounds (eg. most gases, like CO2) have a low melting point.
Yet, water molecules, which are covalent compounds, have a higher melting point than others. It is because water molecules are polar, which allows hydrogen bonds to form among molecules, keeping them close together. More energy is required to melt ice or boil water than normal covalent compounds.
D; You could make some argument for A only but for this the best answer would be D
Answer: The correct answer is -C) Prevent the embryo from drying out.
The amniotic egg of birds and reptiles is surrounded by an outer, tough, and protective shell, which protects the egg from any damage, predators, pathogens, and drying out.
The tough shell and extra embryonic membranes create a safe environment where an embryo can develop into a whole organism (with different organs like eyes ,ears, brain, kidney, heart).
Thus, option C) is the right answer.
Answer:
answer
1. Describe the properties of alkali metals. Based on their electronic arrangement, explain whether they exist alone in nature. 2. Describe an electron
Explanation:
sana maka tulong sa nangangailangan
Percent yield is 108.3%
<u>Explanation:</u>
Percent yield is the ratio of experimental yield and the theoretical yield multiplied by 100.The expression for the percent yield is given as,
Percent yield =
It is given that the experimental or actual yield is 3.9 g and the theoretical yield calculated using stoichiometry is 3.6 g, then the percent yield is calculated as,
Percent yield =
So the percent yield is 108.3%.