Answer:
A high pH value indicates a high concentration of OH- ion
Explanation:
The higher the OH- ion concentration high will be the pH.In simple words if the concentration of OH- ions are increased then the pH of the solution will also increase which means the solution will turns towards basic with increasing its OH- ion concentration.
Let us assume that the OH- concentration of a solution is 10-9 so the pOH of that solution will be 9 and the pH will be 5.
Now the concentration of OH-ion of that solution is increased from 10-9 to 10-8 now the pOH of that solution is 8 and the pH is 6.
Answer:
a) 
b) 
c) 
Explanation:
The symbols of the isotopes are written like
where,
X is the element
A is the mass number (protons + neutrons)
Z is the atomic number (protons)
<em>a) Iodine-131</em>
The atomic number of iodine is 53. The mass number of this isotope is 131. The symbol is .
<em>b) Iridium-192</em>
The atomic number of iridium is 77. The mass number of this isotope is 192. The symbol is .
<em>c) Samarium-153</em>
The atomic number of samarium is 62. The mass number of this isotope is 153. The symbol is .
The molecules of hydrogen gas that are formed is when 48.7 g of sodium are added to water is 6.375 x 10²³ molecules
<u><em>calculation</em></u>
2 Na +2H₂O → 2 NaOH +H₂
Step 1: find the moles of sodium (Na)
moles =mass÷ molar mass
from periodic table the molar mass of Na = 23 g/mol
moles= 48.7 g÷ 23 g/mol =2.117 moles
Step 2:use the mole ratio to determine the moles of H₂
from given equation Na:H₂ is 2:1
therefore the moles of H₂ = 2.117 moles x 1/2=1.059 moles
Step 3: find the molecules of H₂ using the Avogadro's law
According to Avogadro's law 1 mole = 6.02 x 10²³ molecules
1.059 moles = ? molecules
by cross multiplication
= [(1.059 moles x 6.02 x10²³ molecules) / 1 mole] =6.375 x 10²³ molecules
