Answer: Option (b) is the correct answer.
Explanation:
A covalent compound is defined as the compound in which sharing of electrons take place between the combining atoms. Generally, when two or more non-metals chemically combine together the it will lead to the formation of a covalent compound.
For example, 
and HCl is also a covalent compound.
And, a compound in which transfer of electrons occur between the combining atoms is known as an ionic compound. Whenever, a metal chemically combines with a non-metal then it will always lead to the formation of an ionic compound.
For example, KI is an ionic compound.
Thus, we can conclude that and HCl are the two substances which are covalent compounds.
Answer:
1) 2.054 x 10⁻⁴ mol/L.
2) Decreasing the temperature will increase the solubilty of O₂ gas in water.
Explanation:
1) The solubility of O₂ gas in water:
- We cam calculate the solubility of O₂ in water using Henry's law: <em>Cgas = K P</em>,
- where, Cgas is the solubility if gas,
- K is henry's law constant (K for O₂ at 25 ̊C is 1.3 x 10⁻³ mol/l atm),
- P is the partial pressure of O₂ (P = 120 torr / 760 = 0.158 atm).
- Cgas = K P = (1.3 x 10⁻³ mol/l atm) (0.158 atm) = 2.054 x 10⁻⁴ mol/L.
2) The effect of decreasing temperature on the solubility O₂ gas in water:
- Decreasing the temperature will increase the solubilty of O₂ gas in water.
- When the temperature increases, the solubility of O₂ gas in water will decrease because the increase in T will increase the kinetic energy of gas particles and increase its motion that will break intermolecular bonds and escape from solution.
- Decreasing the temperature will increase the solubility of O₂ gas in water will because the kinetic energy of gas particles will decrease and limit its motion that can not break the intermolecular bonds and increase the solubility of O₂ gas.
They are nitrogen, oxygen, hydrogen
Carbon-14 is <span>radioactive element is used to determine the absolute age of late pleistocene animal remains because it is abundant in organic matter. Its decay is first-order and its half-life has been determined to be 5730 years which </span><span>means that after </span>5730 years, the amount of carbon<span>−</span>14<span> will be 1/2 of the initial amount.</span>
