<span>-6(-5)+12
Multiply -6 by -5.
Note: Whenever you multiply or divide a negative number by another negative number, it automatically becomes a positive number.
30+12
Add
Final Answer: 42</span>
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
The area and perimeter of the lawn will be 322 square feet and 74 feet. If the lawn will be mowed. Then the area will be used. If the lawn will be surrounded by a rope. Then the perimeter will be used.
<h3>What is a rectangle?</h3>
It is a polygon with four sides. The total interior angle is 360 degrees. A rectangle's opposite sides are parallel and equal, and each angle is 90 degrees. Its diagonals are all the same length and intersect in the center.
The figure below shows a rectangular lawn.
Then the area of the rectangle will be
Area = 23 × 14
Area = 322 square feet
Then the perimeter of the rectangle will be
Perimeter = 2 (23 + 14)
Perimeter = 2 × 37
Perimeter = 74 feet
If the lawn will be mowed. Then the area will be used.
If the lawn will be surrounded by a rope. Then the perimeter will be used.
More about the rectangle link is given below.
brainly.com/question/10046743
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You are inversing for subtraction which is addition so D