<span>7. Colligative properties are directly related to the number of solute particles in a solution
8. chemical formula of sulfuric acid is H2SO4
9. the arhenius base in the choices is LiOH
10. </span><span>A Lewis base is a substance that can donate a pair of electrons
14. basic
15. weak base
</span>
<u>Answer:</u> The partial pressure of oxygen is 160 mmHg
<u>Explanation:</u>
We are given:
Percent of oxygen in air = 21 %
Mole fraction of oxygen in air = 
To calculate the partial pressure of oxygen, we use the equation given by Raoult's law, which is:

where,
= partial pressure of oxygen = ?
= total pressure of air = 760 mmHg
= mole fraction of oxygen = 0.21
Putting values in above equation, we get:

Hence, the partial pressure of oxygen is 160 mmHg
Answer:
B
Explanation:
H2 + Cl2 → 2HCl
Hmm redox reaction.
Energy is needed to break the bonds of H-H in H2 and Cl-Cl in Cl2
The correct option is 58 Fe 2+.
A neutral atom normally has the same number of proton, neutron and electrons, if the number of electrons differ from that of proton, that means that the elements has given some electrons away or it has gained some electrons from another element.
In the question given above, the atomic number of the element is 26 [because the proton number is 26], which means the element is iron. Iron has 24 electrons because it has given two away, so it will have +2. The iron has 32 neutrons instead of 26 so it is an isotope.