Answer:
The answer is the second option
Explanation:
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Explanation:
The problem here is to find the atomic number of each of the element given.
Sum the powers of the configuration.
a- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Atomic number is = 2 + 2 + 6 + 2 + 6 + 1 = 19
b- 1s² 2s² 2p⁶ 3s² 3p⁴
Atomic number = 2 + 2 + 6 + 2 + 4 = 16
c- 1s¹
Atomic number = 1
For the reaction 2 K + F2 --> 2 KF,
consider K atomic wt. = 39
23.5 g of K = 0.603 moles, hence following the molar ratio of the balanced equation, 0.603 moles of potassium will use 0.3015 moles of F2. (number of moles, n = 0.3015)
Now, following the ideal gas equation, PV = nRT
P = 0.98 atm
V = unknown
n = 0.3015 moles
R = 82.057 cm^3 atm K^-1mole^-1 (unit of R chosen to match the units of other parameters; see the reference below)
T = 298 K
Solving for V,
V = (nRT)/P = (0.3015 mol * 82.057 cm^3 atm K^-1 mol^-1 * 298 K)/(0.98 atm)
solve it to get 7517.6 cm^3 as the volume of F2 = 7.5176 liters of F2 gas is needed.
2. Use the formula: volume1 * concentration 1 = volume 2 * concentration 2
where, volume 1 and concentration 1 are for solution 1 and volume 2 and solution 2 for solution 2.
Solution 1 = 12.3 M NaOH solution
Solution 2 = 1.2 M NaOH solution
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Solving for volume 1, volume 1 = (12.4 L * 1.2 M)/12.3 M = 0.1366 L </span>
2 ways to do this
a. find %Cl in CaCl2
2 x 35.45g/mole = 70.9g Cl
70.9g Cl / 110.9g/mole CaCl2 = 63.93% Cl in CaCl2
0.6963 x 145g = 92.7g = mass Cl
b. determine moles CaCl2 present then mass Cl
145g / 110.9g/mole = 1.31moles CaCl2 present
2moles Cl / 1mole CaCl2 x 1.31moles = 2.62moles Cl
2.62moles Cl x 35.45g/mole = 92.7g Cl
