Answer is 74,844 calories
Answer:
27.0
Explanation:
Because Mass can neither be created nor be destroyed hence total mass of sample of iodine and tube remain equal as it is sealed.
<span>There
are a number of ways to express concentration of a solution. This includes
molarity. Molarity is expressed as the number of moles of solute per volume of
the solution. We calculate the mass of the solute by first determining the number of moles needed. And by using the molar mass, we can convert it to units of mass.
Moles </span>(nh4)3po4 = 0.250 L (0.150 M) = 0.0375 moles (nh4)3po4
Mass = 0.0375 mol (nh4)3po4 (149.0867 g / mol) = 5.59 g (nh4)3po4
Answer:
pH = 2.32
Explanation:
H2A + H2O -------> H3O+ + HA-
Ka2 is very less so i am not considering that dissociation.
now Ka = 8.0×10−5
= [H3O+] [HA-] / [H2A]
lets concentration of H3O+ = X then above equation will be
8.0×10−5 = [X] [X] / [0.28 -X]
8.0×10−5 = X2 / [0.28 -X]
X2 + 8.0×10−5 X - 2.24 x 10−5
solve the quardratic equation
X =0.004693 M
pH = -log[H+}
= -log [0.004693]
= 2.3285
≅2.32
pH = 2.32
Answer:
83°C
Explanation:
The following were obtained from the question:
M = 40g
C = 4.2J/g°C
T1 = 91°C
T2 =?
Q = 1300J
Q = MCΔT
ΔT = Q/CM
ΔT = 1300/(4.2x40)
ΔT = 8°C
But ΔT = T1 — T2 (since the reaction involves cooling)
ΔT = T1 — T2
8 = 91 — T2
Collect like terms
8 — 91 = —T2
— 83 = —T2
Multiply through by —1
T2 = 83°C
The final temperature is 83°C
