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BHC Vic

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I don’t know if I’m tired or what but can someone explain why… what did we do to one side to get here or how did we get here. It’s question 9. In probably over thinking it but I’m getting pissed off now.
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I’d rather be packing for the trip and that’s probably the biggest issue here
 
shintoooo

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  1. Step 1…Substitute the given values into the formula.
    • mg/m3=(ppm)⋅molecular weight24.45mg/m cubed equals open paren ppm close paren center dot the fraction with numerator molecular weight and denominator 24.45 end-fraction
    • mg/m3=9.2⋅7824.45mg/m cubed equals 9.2 center dot 78 over 24.45 end-fraction

    Step 2…Calculate the concentration.
    • mg/m3=9.2⋅7824.45mg/m cubed equals 9.2 center dot 78 over 24.45 end-fraction
    • mg/m3≈29.2mg/m3mg/m cubed is approximately equal to 29.2 space m g / m cubed

  • Understanding Units of Measurement - gov.epa.cfpub
    The molecular weight of benzene is 78. If the concentration of benzene in air is 10 mg/m3, convert to the units of ppm by multiply...

Solution
The concentration of benzene is approximately
29.2mg/m329.2 space m g / m cubed
.
 
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96motorhead

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First you need to understand that whatever you do to one side of the equation must be done to the opposite side to keep the entire equation balanced.

- multiplication will undo division
- division will undo multiplication

1. Multiply both sides by MW, this will give you MW*ppm = (mg/m^3)*24.45
2. Divide both sides by 24.45, this will give you (MW*ppm)/24.45 = mg/m^3

If you just want to cheat the system you can just plug in the answers and see which one gives you 9.2, that will be the correct answer.
 
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BHC Vic

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96motorhead said:
First you need to understand that whatever you do to one side of the equation must be done to the opposite side to keep the entire equation balanced.

- multiplication will undo division
- division will undo multiplication

1. Multiply both sides by MW, this will give you MW*ppm = (mg/m^3)*24.45
2. Divide both sides by 24.45, this will give you (MW*ppm)/24.45 = mg/m^3

If you just want to cheat the system you can just plug in the answers and see which one gives you 9.2, that will be the correct answer.
Click to expand...
Thank you. This helped, I got it now.
 
lbhsbz

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I got 28.2, so I picked the correct the answer because it was closest...lol
 
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Anything from removing a seized broken stud on a Ford V6 block. To using KY jell or oil, to complex math equations,, you’ll find the answer on RDP.
 
sonicss31

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Ok, am I the only that doesn’t understand the question or answer?;)
 
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TPC said:
Anything from removing a seized broken stud on a Ford V6 block. To using KY jell or oil, to complex math equations,, you’ll find the answer on RDP.
Click to expand...
I knew someone would be able to help me understand it. I knew I had to do the same thing to both sides I just wasn’t sure how to isolate what I wanted
 
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rivermobster

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Captain Dan said:
And you might hear yourself say: I'll never need to know algebra. Guess what?
Click to expand...

You do realize most of the world progressed past a pencil and paper a long time ago right? 😁

Screenshot_20241227_113604_Chrome.jpg


 
Terminal Velocity

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BHC Vic said:
I don’t know if I’m tired or what but can someone explain why… what did we do to one side to get here or how did we get here. It’s question 9. In probably over thinking it but I’m getting pissed off now. View attachment 1463666 View attachment 1463667
I’d rather be packing for the trip and that’s probably the biggest issue here
Click to expand...
my pea brain, just plugged in each ( A - D) and did the equation (as it also gave the MW) until it gave me the ppm answer that was in the original question.
 
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rivermobster said:
You do realize most of the world progressed past a pencil and paper a long time ago right? 😁

View attachment 1463924

Click to expand...
I think I need the t85 for this test 😂
 
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Captain Dan said:
Almost 40 years as a Professional Engineer. I've always said if you can't do it by hand, you have no business doing it with a calculator.
Click to expand...
That’s why I wanted someone to explain it to me. I’m not 100% sure we get to use a calc. I’m feeling pretty confident today though. Just aced the practice test. I
 
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Captain Dan

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BHC Vic said:
That’s why I wanted someone to explain it to me. I’m not 100% sure we get to use a calc. I’m feeling pretty confident today though. Just aced the practice test. I
Click to expand...
Good for you, I hope you do well.
 
rivermobster

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Captain Dan said:
Almost 40 years as a Professional Engineer. I've always said if you can't do it by hand, you have no business doing it with a calculator.
Click to expand...

An engineer eh? 🤔😁

Wouldn't that be like saying...

If you can't remove a lug nut by hand, you have no business using an impact? How do you think that would play out on an earth moving machine?

Almost every tool out there, from a calculator to drill motor, was designed to make someone's life easier.

I like easy. Especially when it comes to women. 😎

Full disclosure: I couldn't do algebra even With a calculator! Did I mention I hate math?? 😁
 
lbhsbz

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BHC Vic said:
I knew someone would be able to help me understand it. I knew I had to do the same thing to both sides I just wasn’t sure how to isolate what I wanted
Click to expand...
The original equation had mg/cubic mm (ccs) so I just called that "Y" and re-wrote it....that way you don't get hung up with exponents doings the PEMDAS thing.

Then it gets relatively simple....unless you're a Ford or Union guy I guess....maybe if Ford and Union guys tried breathing through their noses math wouldn't be so hard. lol
 
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