First, we need to calculate moles of hydrazoic acid NH3:
moles NH3 = molarity * volume
= 0.15 m * 0.025 L
= 0.00375 moles
moles NaOH = molarity * volume
= 0.15 m * 0.015 L
= 0.00225 moles
after that we shoul get the total volume = 0.025L + 0.015L
= 0.04 L
So we can get the concentration of NH3 & NaOH by:
∴[NH3] = moles NH3 / total volume
= 0.00375 moles / 0.04 L
= 0.09375 M
∴[NaOH] = moles NaOH / total volume
= 0.00225 moles / 0.04 L
= 0.05625 M
then, when we have the value of Ka of NH3 so we can get the Pka value from:
Pka = -㏒Ka
= - ㏒ 1.9 x10^-5
= 4.7
finally, by using H-H equation we can get PH:
PH = Pka + ㏒[salt/ basic]
PH = 4.7 +㏒[0.05625/0.09375]
∴ PH = 4.48
Answer:
The correct answers are first, fourth, fifth
Explanation:
The objects that are rubbed together will create charges among themselves due to friction.
(1) The balloon rubbed with a wool cloth will be charged.
(2) If she comb near a small, uncharged object nothing will change.
(3) This is a scientific investigation because it does not involved a step by step process to answer a scientific query.
Answer: the density of the solid metal is 22.5176 g/cm
Explanation:
Given that;
mass of solid metal = 255 g
the cylinder and its contents weigh 101g less than before
also given that density of mercury = 13.6 g/cm³
Volume of the solid metal = volume of mercury which was absent in the first weighing
so let volume = Vcm³
Mass of mercury which was absent in the first weighing = density × volume
= 13.6 g/cm³ × Vcm³ = 13.6V g
now since the cylinder and its contents weigh 101g less than before,
it means the difference in mass between the solid and metal and the mass of mercury is equal to 101 g
so
255 - 13.6V g = 101g
13.6V g = 255 g - 101 g
13.6V = 154
V = 154 / 13.6
V = 11.3245 cm³
Now Density of solid metal will be;
⇒ mass / volume
= 255 / 11.3245
= 22.5176 g/cm
Therefore, the density of the solid metal is 22.5176 g/cm
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