Answer:
Endothermic means: accompanied by or requiring the absorption of heat. So therefor cold packs would not be endothermic because they don't release cold. Instead they absorb heat
Explanation:
Answer:
pH=10.97
Explanation:
the solution of methyl amine with methylammonium chloride will make a buffer solution.
The pH of buffer solution can be obtained using Henderson Hassalbalch's equation, which is:
![pOH=pKb+log\frac{[salt]}{[base]}](https://tex.z-dn.net/?f=pOH%3DpKb%2Blog%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bbase%5D%7D)
pH = 14- pOH
Let us calculate pOH

[Salt] = [methylammonium chloride] = 0.10 M (initial)
After adding base
![[salt] = \frac{molarityXvolume}{finalvolume}=\frac{0.1X20}{(20+50)}= 0.0286M](https://tex.z-dn.net/?f=%5Bsalt%5D%20%3D%20%5Cfrac%7BmolarityXvolume%7D%7Bfinalvolume%7D%3D%5Cfrac%7B0.1X20%7D%7B%2820%2B50%29%7D%3D%200.0286M)
[base] = [Methylamine]=0.10
After mixing with salt
![[base]= \frac{molarityXvolume}{finalvolume}=\frac{0.1X50}{(20+50)}= 0.0714M](https://tex.z-dn.net/?f=%5Bbase%5D%3D%20%5Cfrac%7BmolarityXvolume%7D%7Bfinalvolume%7D%3D%5Cfrac%7B0.1X50%7D%7B%2820%2B50%29%7D%3D%200.0714M)
pKb= -log[Kb]= 3.43
Putting values
pOH = ![3.43+log(\frac{[0.0286]}{0.0714}](https://tex.z-dn.net/?f=3.43%2Blog%28%5Cfrac%7B%5B0.0286%5D%7D%7B0.0714%7D)
28.02g ------ 1 mol
X g ------------ 4.60 mol
X = (28.02×4.60)/1
X = 128,892 g
Answer:
It take 3.5 *10² min
Explanation:
Step 1: Data given
Mass of the nickel = 29.6 grams
4.7A
Step 2: The balanced equation
Ni2+ (aq- +2e- → Ni(s)
Step 3: Calculate time
W = (ItA)/(n*F)
⇒ W = weight of plated metal in grams = 29.6
⇒ I = current in coulombs per second.
= 4.7
⇒ t = time in seconds.
⇒ A = atomic weight of the metal in grams per mole. = 58.69
⇒ n = valence of dissolved metal in solution in equivalents per mole. = 2
⇒ F = Faraday's constant in coulombs per equivalent. F = 96,485.309 coulombs/equivalent.
29.6 = (4.7 * t * 58.69)/(2*96485309)
t = 20707 seconds
t =345 minutes = 3.5 * 10² min
It take 3.5 *10² min
Answer:
9.2x10²g
Explanation:
Data obtained from the question include the following:
Density = 0.92g/ml
Volume = 1L = 1 x 1000 = 1000mL
Mass =..?
Density is simply defined as the mass of the substance per unit volume of the substance. Mathematically it can be represented as:
Density = Mass /volume.
Mass = Density x volume
Mass = 0.92 x 1000
Mass = 9.2x10²g.
Therefore, 1L of olive will weigh 9.2x10²g.