Answer:-
Solution:- As is clear from the given Ka value, Cinnamic acid is a weak acid. let's calculate the moles of acid and KOH added to it from their given molarities and mL.
For KOH, 
= 0.002 mol
For Cinnamic acid, 
= 0.003 mol
Acid and base react as:
The reaction takes place in 1:1 mol ratio. Since the moles of acid are in excess, the acid is still remaining when all the kOH is used.
0.002 moles of KOH react with 0.002 moles of Cinnamic acid to form 0.002 moles of potassium cinnamate. Excess moles of Cinnamic acid = 0.003 - 0.002 = 0.001
As the solution have weak acid and it's salt(or we could say conjugate base), it is a buffer solution and the pH of the buffer solution could easily be calculated using Handerson equation:
pKa could be caluted from given Ka value using the formula:
pKa = - log Ka
pKa = 4.44
let's plug in the values in Handerson equation and calculate the pH:
pH = 4.44+0.30
pH = 4.74
So, the first choice is correct, pH is 4.74.
5.20 mol C6H12* (84.2 g/mol C6H12)= 4.38*10^(2) g C6H12.
The answer should only have three significant figures, according to the numbers in the problem.
Hope this is helpful~
Answer:
Moles of carbon dioxide gas is 0.584 moles.
Mass of 0.584 moles of carbon dioxide gas is 25.7 g
Explanation:
Using ideal gas equation
PV = nRT
where,
P = Pressure of gas = 
V = Volume of gas = 30.0 L
n = number of moles of gas = ?
R = Gas constant = 0.0821 L.atm/mol.K
T = Temperature of gas = 27°C = 300.15 K
Putting values in above equation, we get:
Moles of carbon dioxide gas = 0.584 moles
Mass of 0.584 moles of carbon dioxide gas = 0.584 mol × 44 g/mol = 25.69 g ≈ 25.7 g
Answer:
Fe(NO₃)₃ + 3KSCN → Fe(SCN)₃ + 3KNO₃
Explanation:
Chemical equation:
Fe(NO₃)₃ + KSCN → Fe(SCN)₃ + KNO₃
Balanced Chemical equation:
Fe(NO₃)₃ + 3KSCN → Fe(SCN)₃ + 3KNO₃
Type of reaction:
It is double displacement reaction.
In this reaction the anion or cation of both reactants exchange with each other. In given reaction the cation Fe⁺³ exchange with cation K⁺.
The given reaction equation is balanced so there are equal number of atoms of each elements are present on both side of equation and completely hold the law of conservation of mass.
Double replacement:
It is the reaction in which two compound exchange their ions and form new compounds.
AB + CD → AC +BD
Conc = moles / Vol you have C but need to find moles
moles KCl = mass / molar mass
25 g / 74.55 g,p;
0.335 moles
So rearrange the formula to find volume. Vol = moles / Conc
0.335 moles / 0.750 mol / L = 0.447 L or 447 mL
The answer in this question is 447 mL.
