PH is calculated using <span>Handerson- Hasselbalch equation,
pH = pKa + log [conjugate base] / [acid]
Conjugate Base = Acetate (CH</span>₃COO⁻)
Acid = Acetic acid (CH₃COOH)
So,
pH = pKa + log [acetate] / [acetic acid]
We are having conc. of acid and acetate but missing with pKa,
pKa is calculated as,
pKa = -log Ka
Putting value of Ka,
pKa = -log 1.76 × 10⁻⁵
pKa = 4.75
Now,
Putting all values in eq. 1,
pH = 4.75 + log [0.172] / [0.818]
pH = 4.072
Answer is: 48,25 torr.
Raoult's Law: p = x(solv) · p(solv)
p - <span>vapour pressure of a solution.
</span>x(solv) - <span>mole fraction of the solvent.
</span>p(solv) - <span>vapour pressure of the pure solvent.
</span>n(ethanol) = 950g ÷ 46,07g/mol = 20,62 mol.
x(solv) = moles of solvent ÷ total number of moles
x(solv) = 20,62 ÷ 21,77 = 0,965.
p = 0,965 ·50,0 torr = 48,25 torr.
Answer:
This question is incomplete and unclear; the complete question including the missing part is:
Emelie is working on a science project. Her task is to answer the question:
"Does Rogooti (a hair cream sold on TV) affect the speed of hair growth
(in length)". Her family is willing to volunteer for the experiment. Identify the control group (CG) and the independent and dependent variables.
ANSWER:
Independent variable: Rogooti hair cream
Dependent variable: Speed of hair growth/length
Control group: Family members that do not use the Rogooti hair cream
Explanation:
In an experiment, the independent variable is the variable that the experimenter changes or manipulates in order to bring about a measurable response. In this case, the ROGOOTI HAIR CREAM is the independent variable.
Dependent variable refers to the variable that is measured or the variable that responds to the change made to the independent variable. In this case, the dependent variable is SPEED AT WHICH HAIR GROWS (IN LENGTH).
Control group in an experiment is the group that does not receive the experimental treatment. In this case, the experimental treatment is the Rogooti hair cream, hence, the control group will be the VOLUNTEER FAMILY MEMBERS THAT DOES NOT RECEIVE THE ROGOOTI HAIR CREAM ON THEIR HAIR.
To determine the time it takes to completely vaporize the given amount of water, we first determine the total heat that is being absorbed from the process. To do this, we need information on the latent heat of vaporization of water. This heat is being absorbed by the process of phase change without any change in the temperature of the system. For water, it is equal to 40.8 kJ / mol.
Total heat = 40.8 kJ / mol ( 1.50 mol ) = 61.2 kJ of heat is to be absorbed
Given the constant rate of 19.0 J/s supply of energy to the system, we determine the time as follows:
Time = 61.2 kJ ( 1000 J / 1 kJ ) / 19.0 J/s = 3221.05 s
Answer:The endpoint does not correspond exactly to the equivalence point
At the endpoint, a change in a physical quantity associated with the equivalence point occurs.
At the equivalence point, the mole number of equivalents of reagent added is equal to the mole number of equivalents of analyte present.
Explanation:
The end point is always indicated by some physical property that changes such as colour. At the equivalence point, the mole number of equivalents of reagent added is equal to the mole number of equivalents of analyte present. The equivalence point cannot be physically observed but can be deduced after a titration curve is plotted.
