Mean is
and a standard deviation is
, then the variable
.
Use substitution
.
This substitution gives you that
.
a. For X=130,
and
(the decimal value is taken from the Standard Normal Distribution Table).
b. For X=90,
and for X=110,
. Then
(the decimal value is taken from the Standard Normal Distribution Table).
So this is the answer:)))))
1.326 grams of NH3 are required to produce 4.65 g of HF.
Step-by-step explanation:
Balanced chemical reaction is written first to know the number of moles taking part in original reaction.
NH3 +3 F2 ⇒3 HF + NF3
Given:
mass of HF = 4.65
First the number of moles of HF in 4.65 grams is calculated by using the formula:
number of moles (n) = 
atomic mass of HF = 20 grams/mole
putting the values in the above equation number of moles can be found.
n = 
= 0.235 moles of HF are given.
From the equation it can be said that:
1 mole of NH3 reacts to form 3 moles of HF
so, x moles of NH3 would react to form 0.235 moles of HF
= 
3x = 0.235
x = 
x = 0.078 moles of NH3 is required.
The moles are converted to mass by applying the formula:
mass = atomic mass X number of moles (atomic mass of NH3 = 17 grams/mole)
putting the values in the formula
mass = 17 X 0.078
mass = 1.326 grams
Answer:
<u>The correct answer is 35.4%</u>
Step-by-step explanation:
Let's check the information provided in the question:
Savings goal = US$ 2,000 for the club trip
Earnings for the candles selling = US$ 708
For calculating the accumulated percentage, we can do it this way:
Accumulated percentage = Earnings / Savings goal
Accumulated percentage = 708 / 2,000 * 100
Accumulated percentage = 0.354 * 100
<u>Accumulated percentage = 35.4%</u>
<u>Students at Maple School has accumulated 35.4% of their savings goal with the candles selling.</u>