Answer:
Mass = 23.36 g
Explanation:
Given data:
Number of particles of CO₂ = 3.20 ×10²³
Mass of CO₂ = ?
Solution:
1 mole contain 6.022×`10²³ particles,
3.20 ×10²³ particles × 1 mol / 6.022×`10²³ particles
0.531 mol
Mass of CO₂:
Mass = number of moles × molar mass
Molar mass = 44 g/mol
Mass = 0.531 mol× 44 g/mol
Mass = 23.36 g
Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M
Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M
Answer: (A) 
(B) 
Explanation:
(A) As we know that HCl is a strong acid and when it is added to an aqueous solution then it leads to increase in the concentration of hydrogen ions. And, when an acid or base is added to a solution then any resistance by the solution in changing the pH of the solution is known as a buffer.
This means that addition of buffer into the given solution will not cause much change in the concentration of 
in large amount.
As both the buffer components are salt then they will remain dissociated as follows.
Hence, net ionic equation will be as follows.
(B) When we add small amount of sodium hydroxide into the solution then there will occur an increase in concentration of hydroxide ions into the solution. But then due to the presence of buffer there will occur not much change in concentration and the acid will get converted into salt.
The net ionic equation is as follows.
Antoine Lavoisier was part of a wealthy family in Paris. He pursued to study science upon realizing that chemistry or the study of the elements was not a well-studied field. His discovery of that air was a mixture of nitrogen and oxygen gave rise to the concept of COMBUSTION after repeating the experiments made by Priestly using mercury and other metal oxides.
The event was such a history-making because it disproved that concept that air was a pure substance along with 3 others: earth, fire, and water.
Answer: higher b. Among compounds of approximately the same molar mass, those with greater polarities tend to have Wiesenthal of vaporization that are (higher, lower.
Explanation: Molecules in a gas are far apart. They are mulct"\ closer together in a liquid. Molecules in a gas are easily squeezed closer together as the gas is compressed and walls more frequently than before and with a greater force per impact.
