Explanation:
There are 1000 m in a km, and 100 cm in a m.
2.85×10¹² km × (1000 m / km) × (100 cm / m) = 2.852.85×10¹⁷ cm
Answer:
Percent yield = 79.79 %
Explanation:
Given data:
Mass of Al₂O₃ = 821 g
Mass of Al = 349 g
Percent yield = ?
Solution:
Chemical equation:
2Al₂O₃ + 3C → 4Al + 3CO₂
Number of moles of Al₂O₃:
Number of moles = mass/molar mass
Number of moles = 821 g/ 101.96 g/mol
Number of moles = 8.1 mol
Now we will compare the moles of Al with Al₂O₃.
Al₂O₃ : Al
2 : 4
8.1 : 4/2×8.1 = 16.2 mol
Mass of Al:
Mass = number of moles × molar mass
Mass = 16.2 mol × 27 g/mol
Mass = 437.4 g
Percent yield:
Percent yield = (actual yield / theoretical yield)× 100
Percent yield = (349 g/ 437.4 g) × 100
Percent yield = 79.79 %
It is necessary to dilute the given substances prior to determining the pH because the concentrated solutions prevent contact with the pH meter and give lower values.
A solution's acidity may be determined by looking at its pH, which is a measurement of hydrogen ion concentration. Pure water slightly separates into ions with roughly equal amounts of hydrogen and hydroxyl (OH) ions.
Detergents, soaps, and shampoos all include surfactants, and when they are concentrated, their activity prevents the surfactant from making adequate contact with the pH meter's electrode, resulting in readings that are a little lower than they should be. The pH is determined correctly when the surfactant activity is diluted in the solution.
Learn more about pH of a solution here:
brainly.com/question/11300720
#SPJ4
Volume is directly proportional to the number of moles.
Answer:
NH3 weak base
HCOOH weak acid
H3PO4 weak acid
NaOH strong base
Explanation:
When talking about the weakness or strength of acid and bases, it is essential to look at it from the base point of ionization or dissociation in solutions. For an acid or base to be termed strong , this means it ionize completely in solution to form hydroxonium ion and hydroxide jobs respectively in water. For an acid or base to be termed weak, it ionizes only partially in solution.
The strength of acid can be accessed from the value of the acid ionization constant Ka. Strong acids like sulphuric acid have a fairly large value for for this constant while weak acids have a relatively low value for this constant. Hence, we must know that the dissociation equation is not enough to say an acid is weak or strong. Acids with higher Ka value are stronger with acids with lower Ka value.
In likewise manner, we have the base dissociation constant. It is the equilibrium constant for a base dissociation reaction. While stronger bases have relatively higher values for Ka, weak bases have a relatively lower value.
Ammonia yields a weak base solution of ammonium hydroxide in water. This makes it a weak acid
Methanoic or Formic acid like most organic acid is a weak acid. It ionizes only partially in solutions.
Phosphoric acid is also a weak acid as it ionizes partially in solutions too.
Lastly, sodium hydroxide is a strong base as it ionizes completely in solution