Answer:
its B
Explanation:
trust me i had this in my usatestprep, also follow me on tiktok, its ultrasolos
Answer:
pH =3.8
Explanation:
Lets call the monoprotic weak acid HA, the dissociation equilibria in water will be:
HA + H₂O ⇄ H₃O⁺ + A⁻ with Ka = [ H₃O⁺] x [A⁻]/ [HA]
The pH is the negative log of the H₃O⁺ concentration, we know the equilibrium constant, Ka and the original acid concentration. So we will need to find the [H₃O⁺] to solve this question.
In order to do that lets set up the ICE table helper which accounts for the species at equilibrium:
HA H₃O⁺ A⁻
Initial, M 0.40 0 0
Change , M -x +x +x
Equilibrium, M 0.40 - x x x
Lets express these concentrations in terms of the equilibrium constant:
Ka = x² / (0.40 - x )
Now the equilibrium constant is so small ( very little dissociation of HA ) that is safe to approximate 0.40 - x to 0.40,
7.3 x 10⁻⁶ = x² / 0.40 ⇒ x = √( 7.3 x 10⁻⁶ x 0.40 ) = 1.71 x 10⁻³
[H₃O⁺] = 1.71 x 10⁻³
Indeed 1.71 x 10⁻³ is small compared to 0.40 (0.4 %). To be a good approximation our value should be less or equal to 5 %.
pH = - log ( 1.71 x 10⁻³ ) = 3.8
Note: when the aprroximation is greater than 5 % we will need to solve the resulting quadratic equation.
Answer:
= 3.56 atm
Explanation:
Using Boyle's law which states that the volume of a given mass of gas is inversely proportional to the pressure and Charles law states the volume of a given mass of gas is directly proportional to the temperature.
P1/T1 = P2/T2
P1 = 3.1 atm, T1 = 100'C = 100+273 = 373K
T2 = 155'C = 155 + 273 = 428K
3.1/ 373 = P2 / 428
Cross multiply
373 × P2 = 3.1 × 428
373×P2 = 1326.8
Divide both sides by 373
P2 = 1326.8 ÷ 373
P2 = 3.56 atm
I hope this was helpful, please mark as brainliest
Answer:
The answer to your question is 178.6 g
Explanation:
Data
ΔT = 1.8 °C
mass = 17.5 g
mass of water = 100 g
Kc = 1.86
Process
1.- Calculate the molality using the following formula
ΔTc = mKc
solve for m
m = ΔTc/Kc
substitution
m = 1.8/1.86
result
m = 0.968
2.- Calculate the number of moles
m = # of moles/kg of solvent
kg of solvent = 0.1 kg
# of moles = m x kg of solvent
# of moles = 0.968 x 0.1
# of moles = 0.0968
3.- Calculate the molar mass
x g molar mass --------------------- 1 mol
17.5 g --------------------- 0.0968 moles
x = (1 x 17.5)/0.0968
x = 178.6 g
Before making a hypothesis, a scientist should make observations and conduct research.
I hope this helps.
