We will get the molality from this formula:
Molality = no.of moles of solute / Kg of solvent
So first we need the no.of moles of KNO3 = the mass of KNO3 / molar mass of KNO3
no.of moles of KNO3 = 175 / 101.01 = 1.73 mol
By substitution in the molality formula:
∴ molality = 1.73 / (750/1000) = 2.3 Molal
It knows that when water evaporates, it carries heat energy away with it.
So your body puts some water out on your skin, and hopes that it will
evaporate. We call that "perspiring" or "sweating".
Answer:
D = m/V
Explanation:
Density represents the following ratio:
Density (D) = mass (m) / volume (V)
In this formula, the volume is being divided from the mass. The typical units for mass is grams and the unit for volume is milliliters.
Answer :
(A) The rate expression will be:
![Rate=-\frac{1}{2}\frac{d[HBr]}{dt}=+\frac{d[H_2]}{dt}=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=Rate%3D-%5Cfrac%7B1%7D%7B2%7D%5Cfrac%7Bd%5BHBr%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7Bd%5BH_2%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
(B) The average rate of the reaction during this time interval is, 0.00176 M/s
(C) The amount of Br₂ (in moles) formed is, 0.0396 mol
Explanation :
Rate of reaction : It is defined as the change in the concentration of any one of the reactants or products per unit time.
The given rate of reaction is,

The expression for rate of reaction :
![\text{Rate of disappearance of }HBr=-\frac{1}{2}\frac{d[HBr]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20%7DHBr%3D-%5Cfrac%7B1%7D%7B2%7D%5Cfrac%7Bd%5BHBr%5D%7D%7Bdt%7D)
![\text{Rate of disappearance of }H_2=+\frac{d[H_2]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20disappearance%20of%20%7DH_2%3D%2B%5Cfrac%7Bd%5BH_2%5D%7D%7Bdt%7D)
![\text{Rate of formation of }Br_2=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BRate%20of%20formation%20of%20%7DBr_2%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
<u>Part A:</u>
The rate expression will be:
![Rate=-\frac{1}{2}\frac{d[HBr]}{dt}=+\frac{d[H_2]}{dt}=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=Rate%3D-%5Cfrac%7B1%7D%7B2%7D%5Cfrac%7Bd%5BHBr%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7Bd%5BH_2%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
<u>Part B:</u>
![\text{Average rate}=-\frac{1}{2}\frac{d[HBr]}{dt}](https://tex.z-dn.net/?f=%5Ctext%7BAverage%20rate%7D%3D-%5Cfrac%7B1%7D%7B2%7D%5Cfrac%7Bd%5BHBr%5D%7D%7Bdt%7D)


The average rate of the reaction during this time interval is, 0.00176 M/s
<u>Part C:</u>
As we are given that the volume of the reaction vessel is 1.50 L.
![\frac{d[Br_2]}{dt}=0.00176M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D%3D0.00176M%2Fs)
![\frac{d[Br_2]}{15.0s}=0.00176M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BBr_2%5D%7D%7B15.0s%7D%3D0.00176M%2Fs)
![[Br_2]=0.00176M/s\times 15.0s](https://tex.z-dn.net/?f=%5BBr_2%5D%3D0.00176M%2Fs%5Ctimes%2015.0s)
![[Br_2]=0.0264M](https://tex.z-dn.net/?f=%5BBr_2%5D%3D0.0264M)
Now we have to determine the amount of Br₂ (in moles).



The amount of Br₂ (in moles) formed is, 0.0396 mol

Formula mass of CaCO3 is
40 + 12 + 3-100amu....
100g CaCO3 = 1 mole..
50g of CaCO3 = 1÷ 100x 5 = 0.5mole...
<h3>Hence ,answer is 0.5mole...</h3>

Hope it helps you..
Thanks...