<u>Answer:</u> The mass of calcium chloride present in given amount of solution is 87.5 g
<u>Explanation:</u>
We are given:
Mass of solution = 277.8 grams
Also, 31.5 % (m/m) of calcium chloride in water. This means that 31.5 g of calcium chloride is present in 100 g of solution.
To calculate the mass of calcium chloride in the given amount of solution, we use unitary method:
in 100 g of solution, the mass of calcium chloride present is 31.5 g
So, 277.8 g of solution, the mass of calcium chloride present is
Hence, the mass of calcium chloride present in given amount of solution is 87.5 g
Answer:
13.20 cm/s is the rate at which the water level is rising when the water level is 4 cm.
Explanation:
Length of the base = l
Width of the base = w
Height of the pyramid = h
Volume of the pyramid = 
We have:
Rate at which water is filled in cube = 
Square based pyramid:
l = 6 cm, w = 6 cm, h = 13 cm
Volume of the square based pyramid = V





Differentiating V with respect to dt:




Putting, h = 4 cm


13.20 cm/s is the rate at which the water level is rising when the water level is 4 cm.
Answer:
0.21mol Ar (g)
Explanation:
To convert from litres to moles at STP we must divide the amount of litres by 22.4.
4.7 / 22.4 = 0.21mol Ar (g)
PH of acidic buffer = pKa + log [CH₃COONa - HCl] / [CH₃COOH + HCl]
pKa of CH₃COOH = 4.74
Concentration of acetic acid in buffer = 2.0 M
Concentration of sodium acetate = 1.0 M
Concentration of HCl must add = x
pH = 4.74 + log (1-x) / (2+x) = 4.11
x = concentration of HCl must be added = 0.43 M
number of moles of HCl = M * V = 0.43 * 1 = 0.43 mol
mass of HCl must be added = 0.43 * 36.5 = 15.7 g
The mass and Volume is different even thought they have a similar shape and size