Answer:
(3) 5.36
Explanation:
Since this is a titration of a weak acid before reaching equivalence point, we will have effectively a buffer solution. Then we can use the Henderson-Hasselbalch equation to answer this question.
The reaction is:
HAc + NaOH ⇒ NaAc + H₂O
V NaOH = 40 mL x 1 L/1000 mL = 0.040 L
mol NaOH reacted with HAc = 0.040 L x 0.05 mol/L = 0.002 mol
mol HAC originally present = 0.050 L x 0.05 mol/L = 0.0025 mol
mol HAc left after reaction = 0.0025 - 0.002 = 0.0005
Now that we have calculated the quantities of the weak acid and its conjugate base in the buffer, we just plug the values into the equation
pH = pKa + log ((Ac⁻)/(HAc))
(Notice we do not have to calculate the molarities of Ac⁻ and HAc because the volumes cancel in the quotient)
pH = -log (1.75 x 10⁻⁵) + log (0.002/0.0005) = 5.36
THe answer is 5.36
The electrical charge of an atom having 15 proton, 14 neutrons and 16 electrons is -1. The correct option is D.
What is an atom?
An atom is the smallest unit of any matter which comprises of central nucleus and electrons revolving around the nucleus in definite energy shells. The atom is made up of protons, neutrons and electrons.
The electrical charge of an atom can be calculated as,
Charge of an atom = number of protons - number of electrons
Charge = 15 - 16 = -1.
The neutrons are neutral and do not contribute to the charge, the protons are positively charged and electrons are negatively charged in an atom.
Therefore, the charge of an atom with 15 protons, 14 neutrons and 16 electrons is -1. The correct answer is option D.
To learn more about atom click on the given link brainly.com/question/6258301
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<em>Paper chromatography is especially useful in characterizing amino acids. The different amino acids move at differing rates on the paper because of differences in their R groups.</em>
PV = nRT
R = 0.0821 L * atm / mol * K
(ideal gas constant)
First, convert 735 torr to atm. Divide by 760.
(1 atm = 760 torr)
735 torr * 1 atm / 760 torr = 0.967 atm
Then, convert 37 C to Kelvin. Just add 273.
37 C = 310K
n = PV / RT
= (0.967)(2.07) / (0.0821)(310)
= 0.0786 mol
<span>0.0786 mol * 6.02 * 10^23 molecules / 1 mol = 4.73 * 10^22 molecules </span>
