Answer:
The sum of first 30 terms of the arithmetic progression is <u>2160.</u>
Explanation:
For an arithmetic progression, the sum of first 
terms with first term as 
and common difference 
is given as:
Now, it is given that:
Now, plug in these values and frame two equations in 
Now, we solve equations (1) and (2) for . Subtract equation (1) from equation (2). This gives,
Now, plug in the value of 
in equation (1) and solve for .
Plug in the values of 
in the sum formula to find the sum of first 30 terms.
Now, the sum of first 30 terms is given as:
Therefore, the sum of first 30 terms of the arithmetic progression is 2160.
Answer:
14.336 g MnF₂
Explanation:
number of moles = mass / molecular weight
number of moles of MnI₂ = 55 / 309 = 0.178 moles
number of moles of F₂ = 55 / 38 = 1.447 moles
From the reaction and the number of moles calculated we deduce that the fluorine F₂ is a limiting reactant.
So:
if 13 moles of F₂ reacts to produce 2 moles of MnF₃
then 1.447 moles of F₂ reacts to produce X moles of MnF₃
X = (1.447 × 2) / 13 = 0.223 moles of MnF₃ (100% yield)
For 57.2% yield we have:
number of moles of MnF₃ = (57.2 / 100) × 0.223 = 0.128 moles
mass = number of moles × molecular weight
mass of MnF₃ = 0.128 × 112 = 14.336 g
Answer: The Sun Could Be Seen Once during the year when north of the equator.
