Answer:
b) heating, cooling
Explanation:
Heating will favour dissolution (it helps dissolving faster).
Cooling helps in crystallization.
Answer:
B. choosing a material that will show warning before it fails.
Explanation:
Im a bit torn here, lets look at the definitions of physical and chemical changes:
physical change changes only the phase/state of a substance, but not what the substance is
chemical change is a chemical reaction where a new substance is formed and energy is given off or absorbed.
(it just started raining and it smells really nice out my window)
clearly, this cannot be just a physical reaction. i think i would be inclined to pick B. but C. could have merit as an answer too. sorry for the ambiguity x
Answer:
Explanation:
1) Valence electrons
2) Electrons
3) 2 electrons on K-shell
4) 8 electrons on L-Shell
5) 18 electrons on M-shell
6) nucleus
7) Proton
8) neutron
9) principal energy level
10) atomic number
11) symbol of the atom
12) name of the atom
13) atomic mass
To cut this short and for your understanding, ionic bond is formed between metals (mostly right column in periodic table). Covalent bond is formed between non-metals (mostly left column in periodic table). So polar covalent is also a covalent bond but it is polar, which means the shape of molecules are not symmetrical hence maybe an atom in a molecule has most of the electron attracted to it causing itself to be partial negative (since electron are negatively charged) and the other atom has its electron being attracted by others became partial positive. Polar covalent can also be when H atom is binding either to F, O or N (also known as hydrogen bond).
