Answer:
D: Water is polar, so it can form attractions to and pull apart molecules of many types of substances.
Explanation:
Water is an excellent solvent simply because its polar water molecules usually form hydrogen bonds with ions and polar molecules, thereby allowing the ionic and polar covalent compounds to easily disperse easily in water.
Thus, the correct option is; D
Answer:
Explanation:
According to conservation of energy
q = ΔE + w
q is heat given , ΔE is increase in internal energy and w is work done by the gas.
i )
q = 50 kJ ; w = 30 kJ
Substituting the values
50 kJ = ΔE + 30 kJ
ΔE = 20 kJ ; Hence ΔE is positive.
ii )
q = - 25 kJ ; w = 45 kJ
- 25 kJ = ΔE + 45 kJ
ΔE = - 70 kJ .
ΔE is negative. It is endothermic.
iii )
q = 12.5 kJ ; w = - 3.5 kJ
12.5 kJ = ΔE - 3.5 kJ
ΔE = 16 kJ
Hence ΔE is positive.
Copper is a chemical element having atomic number 29 and represented by the symbol Cu.
The electron configuration of copper is 1s2 2s2 2p6 3s2 3p6 4s1 3d10 and copper will share one atom from s orbital as it can hold two electrons and form one bond with other atoms to become stable.