Explanation:
When there occurs sharing of electrons between two chemically combining atoms then it forms a covalent bond. Generally, a covalent bond is formed between two non-metals.
An ionic bond is defined as the bond formed due to transfer of one or more number of electrons from one atom to another. An ionic bond is always formed between a metal and a non-metal.
Every atom of an element will have orbitals in which electrons are found. These orbitals are known as energy level.
A molecule is defined as the smallest particle present in a substance or atom.
A metallic bond is formed due to mobile valence electrons shared by positive nuclei in a metallic crystal.
Thus, we can conclude that given statements are correctly matched as follows.
1). a chemical bond formed by the electrostatic attraction between ions - ionic bond
2). a chemical bond formed by two electrons that are shared between two atoms - covalent bond
3). the orbitals of an atom where electrons are found - energy level
4). the smallest particle of a covalently bonded substance - molecule
5). a bond characteristic of metals in which mobile valence electrons are shared among positive nuclei in the metallic crystal - metallic bond
I think the answer is ‘repulsion’
Answers:
(a) 30.55 °C
(b) 298 K and 77°F
(c) 204.44 °C and 477.44 K
(d) -320.8 °F and -196 °C
Explanation:
Converting °C into °F;
°F = °C × 1.8 + 32
Converting °F into °C;
°C = °F - 32 ÷ 1,8
Converting °C into K;
K = °C + 273
Converting K into °C;
°C = K - 273
Answer:
ΔH°rxn = - 433.1 KJ/mol
Explanation:
- CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
⇒ ΔH°rxn = 4ΔH°HCl(g) + ΔH°CCl4(g) - 4ΔH°Cl2(g) - ΔH°CH4(g)
∴ ΔH°Cl2(g) = 0 KJ/mol.....pure element in its reference state
∴ ΔH°CCl4(g) = - 138.7 KJ/mol
∴ ΔH°HCl(g) = - 92.3 KJ/mol
∴ ΔH°CH4(g) = - 74.8 KJ/mol
⇒ ΔH°rxn = 4(- 92.3 KJ/mol) + (- 138.7 KJ/mol) - 4(0 KJ/mol) - (- 74.8 KJ/mol)
⇒ ΔH°rxn = - 369.2 KJ/mol - 138.7 KJ/mol - 0 KJ/mol + 74.8 KJ/mol
⇒ ΔH°rxn = - 433.1 KJ/mol
Saliva's buffering capacity and flow of secretion are directly related to the rate and extent of demineralization. ... Saliva can act as a replenishing source and inhibit tooth demineralization during periods of low pH, while promoting tooth remineralization when the pH returns to a neutral state.
