Acidic and basic are two extremes that describe chemicals, just like hot and cold are two extremes that describe temperature. Mixing acids and bases can cancel out their extreme effects, much like mixing hot and cold water can even out the water temperature. A substance that is neither acidic nor basic is neutral.
The character of acidic, basic and neutral is defined by the concentration of hydrogen ions [H+](mol/L). A solution with a concentration of hydrogen ions higher than 10-7mol/L is acidic, and a solution with a lower concentration is alkaline (another way to say basic). Using the formula, pH=-log[H+], a pH of 7 is neutral, a pH less than 7 is acidic, and a pH greater than 7 is basic. As one can see from this formula, ten times a given concentration of hydrogen ions means one unit lower in terms of pH value (higher acidity), and vice versa.
The formula for ph is given by:pH=−log10[H+]
What is the concentration of H+ ions at a pH = 8?
In calculating for the concentration of hydrogen ion, the formula is given by:[H+]=(10)^(-pH)
Solution:
[H+]=(10)^(-8)[H+]=0.00000001 mol/L
What is the concentration of OH– ions at a pH = 8?pH+pOH=148+pOH=14pOH=6
[OH-]=(10)^(-pOH)[OH-]=(10)^(-6)[OH-]=0.000001
What is the ratio of H+ ions to OH– ions at a pH = 2?The ratio is 0.00000001:0.000001 which is equal to 0.01
Answer:
B The water at the bottom of the lake will never freeze
Explanation:
Its simple
The mole fraction of KCl in the solution is 0.1051
calculation
mole fraction of KCl in solution = moles of KCl / total number of moles(moles of KCl +moles of H2O)
moles=mass/molar mass
mass of KCl=32.7g
molar mass of KCl= 39 +35.5
moles of KCl is therefore= 32.7g/74.5 g/mol=0.439 moles
find the moles of H2O= mass of H2O/molar mass
mass of H2O=100-32.7=67.3g
molar mass of H2O=( 1 x2) +16=18 g/mol
moles = 67.3/18 =3.739 moles
total moles=3.739+0.439=4.178 moles
mole fraction is therefore=0.439/4.178=0.1051
B. carbon-13 is not an allotrope of Carbon.
Allotropes<span> are elements on the periodic table that have more than one crystalline form. </span>Isotopes<span> are atoms of the same element with the same atomic number but have a different mass number.
C-13 is an isotope of carbon, not an allotrope.</span>
