Answer:
- <u>Yes,</u> <em>all titrations of a strong base with a strong acid have the same pH at the equivalence point.</em>
This <u>pH is 7.</u>
Explanation:
<em>Strong acids</em> and <em>strong bases</em> ionize completely in aqueous solutions. The ionization of strong acids produce hydronium ions, H₃O⁺, and the ionization of strong bases produce hydroxide ions, OH⁻.
Since the ionization of strong acids and bases progress until completion, there is not reverse reaction.
The definition of pH is pH = - log [H₃O⁺]. Acids have low pH (below 7, and greater than 0) and bases have high pH (above 7 and less than 14). Neutral solutions have pH = 7.
Acid-base titrations are a method to determine the concentration of an acid from the known concentration of a base, or the concentraion of a base from the known concentration of an acid.
The<em> equivalence point</em> of the titration is the point at which the the number of moles of hydronium ions and hydroxide ions are equal.
Then, at that point, the hydronium and hydroxide ions will be in the stoichiometric proportion to form a neutral solution, i.e. the pH of the solution wiill be 7.
An atom of this isotope contains 5 protons and 10-5=5 neutrons.
The answer is A. 1.67 × 10⁻²⁶ kg.
The value given is called the Avogadro's number. It is the number of particles in every 1 mole of any substance. I think this is a trial and error process. Input 6.022x10^23 into your calculator. Add to this a number consisting of the maximum digit which is 9. Apparently, when 10×10¹³ is added, the display already changes. Therefore, the largest number would have to be 10×10¹².
Answer:
B is correct → since temperature can be measured confidently and the variations with temperature are greater ( then the errors in measuring time diminishes)
Explanation:
A is not correct → since the sugar cubes will be still surrounded by water at the temperature chosen regardless of the size of the glass, organising the data by size of the glass is not correct since the glass size does not affect in a significant way to the results ( it could affect the cooling rate of water due to the exposed surface , it but would be insignificant)
C is not correct → since the sugar cubes are approximately of the same size , putting 2 cubes or "n" cubes will not affect the time significantly since each cube is still surrounded by water at the same temperature and behaves independently from others , then each cube dissolves at the same time ( there would be small variations due to the different sizes of the cubes and the small variation due to the limited mass of water)
D is not correct → since the solubility of sugar in water is high , the amount left after the experiment would be very small ( thus the relative errors are high) and the sugar would be contaminated with water in the weighting operation, leading to more errors
B is correct → since temperature can be measured confidently and the variations with temperature are greater ( then the errors in measuring time diminishes)
Explanation:
CaCl2 ⇄ Ca-²+2Cl-¹
1mole⇄1mole+2moles
So from above ..
1mole CaCl2 produce 1mole Ca-² & 2 moles of Cl-².
For 2.5 moles we multiply the above chemical eq. With 2.5
2.5CaCl2⇄2.5Ca-²+5Cl-¹
So from 2.5 moles of CaCl2 we get 2.5 mole calcium ion and 5 moles chloride ion…
