Answer:
Heating a substance increases the speed at which molecules move.
Explanation:
Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Explanation:
Temperature of Solid
Melting temperature of Solid 
Temperature of liquid 
Specific heats of solid ethanol = 0.97 J/gK
Specific heats of liquid ethanol = 2.3 J/gK
Heat required to melt the the 25 g solid
at 159 K
= 159 K - 138 K = 21 K

Heat required to melt and raise the temperature of
upto 223 K
= 223 K - 159 K = 64 K

Total heat to convert solid ethanol to liquid ethanol at given temperature :
(1kJ=1000J)
Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Answer:
ok 3 = 9 15 i got 15 so what
Explanation:
Answer:
A covalent chemical bond is one in which <u>outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals</u>.
Explanation:
Covalent bonds are formed between two atoms having their electronegativity difference less than 1.7. In this type of bonding the valence electrons of one atoms forms molecular bond with the valence electrons of another atom. The electrons are mutually shared.
Covalent bond can be non-polar as for example formed between hydrogen and carbon atoms.
Also, covalent bond can be polar in nature as that formed between hydrogen and chlorine atoms because the chlorine atom is more electronegative and hence attracts the electrons more towards itself making density of electrons less on hydrogen atom.
Models help us better understand the phenomena